O Brien County, IA Population by Age

The median age in O Brien County, IA is 40.7, as per 2021 ACS 5-Year Estimates. Of the total population, 19.92% were under the age of 15, 17.89% aged 15 to 29, 41.89% aged 30 to 64, 15.72% aged 65 to 84, and 4.57% were 85 years of age and older.
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Updated Sep 17, 2023

O Brien County, IA population age distribution

A complete breakdown of O Brien County's age demographics from 0 to 85 years, distributed across 18 age groups is listed in the table below.

Age Group Population % of Total Population
Under 5 years 906 6.41%
5 to 9 years 1,014 7.17%
10 to 14 years 897 6.34%
15 to 19 years 908 6.42%
20 to 24 years 742 5.25%
25 to 29 years 880 6.22%
30 to 34 years 827 5.85%
35 to 39 years 764 5.4%
40 to 44 years 791 5.59%
45 to 49 years 715 5.06%
50 to 54 years 795 5.62%
55 to 59 years 980 6.93%
60 to 64 years 1,051 7.43%
65 to 69 years 851 6.02%
70 to 74 years 628 4.44%
75 to 79 years 355 2.51%
80 to 84 years 389 2.75%
85 years and over 646 4.57%
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O Brien County, IA population by age group

Key stats
4,467
Population under 25 years
3,262
Population aged 25-44
3,541
Population aged 45-64
2,869
Population aged 65+

Sources: U.S. Census Bureau, American Community Survey (ACS) 2021

The graph shows O Brien County's population by age group, with age group on x-axis and the respective age group's percent of the total population on y-axis
O Brien County, IA population by age group. The largest age group was 60-64 years with a poulation of 1,051 (7.43% of the total population). Source: U.S. Census Bureau American Community Survey (ACS) 2017-2021 5-Year Estimates.

The largest age group in O Brien County, IA was for the group of age 60-64 years with a population of 1,051 (7.43%), according to the 2021 American Community Survey.

At the same time, the smallest age group in O Brien County, IA was the 75-79 years with a population of 355 (2.51%).

O Brien County, IA population by age cohort

To better understand the age distribution of O Brien County, IA's population, we divided it into the following 3 cohorts:

  • Children : Under the age of 18 years
  • Adults (working population): Between the age of 18 and 64 years
  • Seniors: 65 years and above
The pie chart shows O Brien County's population divided into segments, with each segment representing an age cohort. The area of each segment is in the same proportion of a circle as the population of the cohort is of the total population.
O Brien County, IA population by age cohorts (Children: Under 18 years; Working population: 18-64 years; Senior population: 65 years or more). The largest age group was 18 - 64 years with a poulation of 7,865 (55.63% of the total population). Source: U.S. Census Bureau American Community Survey (ACS) 2017-2021 5-Year Estimates.

Here's the population for each of the three cohorts.

Age Group Population % of Total Population
Under 18 years 3,405 24.08%
18 to 64 years 7,865 55.63%
85 years and over 2,869 20.29%
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Key stats for each age cohort as per our analysis of U.S. Census Bureau American Community Survey:

  • O Brien County's population under 18 was 24.08%, compared to the 22.51% nationwide.
  • O Brien County's working population (between 18 and 64) was 55.63%, compared to 61.45% nationwide.
  • O Brien County's elderly or the senior population (over 65 age) was 20.29% as compared to 16.04% nationwide.

O Brien County, IA population pyramid

Population pyramid for O Brien County, IA is charted below using the estimates from U.S. Census Bureau's American Community Survey 5-Year estimates. A wide base suggests population increase, narrow base indicates declining birth rates.

Key stats from our analysis of the O Brien County's population pyramid:

  • Youth dependency ratio, which is the number of children aged 0-14 per 100 persons aged 15-64, for O Brien County, IA, is 33.3.
  • Old-age dependency ratio, which is the number of persons aged 65 or over per 100 persons aged 15-64, for O Brien County, IA, is 33.9.
  • Total dependency ratio for O Brien County, IA is 67.3.
  • Potential support ratio, which is the number of youth (working age population) per elderly, for O Brien County, IA is 2.9.
The graph shows O Brien County's population across different age group and gender, with population on x-axis and population y-axis. The male population is plotted on the left in blue color whereas the female population is plotted on the right in pink color.
O Brien County, IA population pyramid i.e. O Brien County population distrubution across age and gender. Source: U.S. Census Bureau American Community Survey (ACS) 2017-2021 5-Year Estimates.

Here's the O Brien County, IA's male and female population across different age groups:

Age Group Population(Male) Population(Female) Total Population
Under 5 years 430 476 906
5 to 9 years 549 465 1,014
10 to 14 years 474 423 897
15 to 19 years 455 453 908
20 to 24 years 407 335 742
25 to 29 years 418 462 880
30 to 34 years 456 371 827
35 to 39 years 412 352 764
40 to 44 years 387 404 791
45 to 49 years 372 343 715
50 to 54 years 434 361 795
55 to 59 years 496 484 980
60 to 64 years 530 521 1,051
65 to 69 years 452 399 851
70 to 74 years 290 338 628
75 to 79 years 186 169 355
80 to 84 years 126 263 389
85 years and over 232 414 646
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Things to know

What is the population of O Brien County, IA under 18?

O Brien County's population under the age of 18 is 3,405, as per the latest U.S. Census Bureau's American Community Survey estimates. This population is 24.08% of the total resident population of O Brien County, IA.

What is the aging population in O Brien County, IA?

O Brien County's population aged 65 years and above was 2,869. As per the U.S. Census Bureau's American Community Survey, this population is 20.29% of the entire population.

References

Datasets

Explore datasets by year of publication.
2023
O Brien County, IA Age Group Population Dataset: A complete breakdown of O Brien County age demographics from 0 to 85 years, distributed across 18 age groups
Last updated September 16, 2023
ACS
Free
Neilsberg
CSV, JSON
2017-2021
CC BY 4.0
About this dataset

Context

The dataset tabulates the O Brien County population distribution across 18 age groups. It lists the population in each age group along with the percentage population relative of the total population for O Brien County. The dataset can be utilized to understand the population distribution of O Brien County by age. For example, using this dataset, we can identify the largest age group in O Brien County.

Key observations

The largest age group in O Brien County, IA was for the group of age 60-64 years with a population of 1,051 (7.43%), according to the 2021 American Community Survey. At the same time, the smallest age group in O Brien County, IA was the 75-79 years with a population of 355 (2.51%). Source: U.S. Census Bureau American Community Survey (ACS) 2017-2021 5-Year Estimates.

O Brien County population by age group

Content

When available, the data consists of estimates from the U.S. Census Bureau American Community Survey (ACS) 2017-2021 5-Year Estimates.

Age groups:

  • Under 5 years
  • 5 to 9 years
  • 10 to 14 years
  • 15 to 19 years
  • 20 to 24 years
  • 25 to 29 years
  • 30 to 34 years
  • 35 to 39 years
  • 40 to 44 years
  • 45 to 49 years
  • 50 to 54 years
  • 55 to 59 years
  • 60 to 64 years
  • 65 to 69 years
  • 70 to 74 years
  • 75 to 79 years
  • 80 to 84 years
  • 85 years and over

Variables / Data Columns

  • Age Group: This column displays the age group in consideration
  • Population: The population for the specific age group in the O Brien County is shown in this column.
  • % of Total Population: This column displays the population of each age group as a proportion of O Brien County total population. Please note that the sum of all percentages may not equal one due to rounding of values.

Good to know

Margin of Error

Data in the dataset are based on the estimates and are subject to sampling variability and thus a margin of error. Neilsberg Research recommends using caution when presening these estimates in your research.

Custom data

If you do need custom data for any of your research project, report or presentation, you can contact our research staff at research@neilsberg.com for a feasibility of a custom tabulation on a fee-for-service basis.

Inspiration

Neilsberg Research Team curates, analyze and publishes demographics and economic data from a variety of public and proprietary sources, each of which often includes multiple surveys and programs. The large majority of Neilsberg Research aggregated datasets and insights is made available for free download at https://www.neilsberg.com/research/.

Recommended for further research

This dataset is a part of the main dataset for O Brien County Population by Age. You can refer the same here

O Brien County, IA Age Cohorts Dataset: Children, Working Adults, and Seniors in O Brien County - Population and Percentage Analysis
Last updated September 16, 2023
ACS
Free
Neilsberg
CSV, JSON
2017-2021
CC BY 4.0
About this dataset

Context

The dataset tabulates the O Brien County population by age cohorts (Children: Under 18 years; Working population: 18-64 years; Senior population: 65 years or more). It lists the population in each age cohort group along with its percentage relative to the total population of O Brien County. The dataset can be utilized to understand the population distribution across children, working population and senior population for dependency ratio, housing requirements, ageing, migration patterns etc.

Key observations

The largest age group was $b3_v1 with a poulation of $b3_v2 ($b3_v3 of the total population). Source: U.S. Census Bureau American Community Survey (ACS) 2017-2021 5-Year Estimates.

O Brien County population by age cohort

Content

When available, the data consists of estimates from the U.S. Census Bureau American Community Survey (ACS) 2017-2021 5-Year Estimates.

Age cohorts:

  • Under 18 years
  • 18 to 64 years
  • 65 years and over

Variables / Data Columns

  • Age Group: This column displays the age cohort for the O Brien County population analysis. Total expected values are 3 groups ( Children, Working Population and Senior Population).
  • Population: The population for the age cohort in O Brien County is shown in the following column.
  • Percent of Total Population: The population as a percent of total population of the O Brien County is shown in the following column.

Good to know

Margin of Error

Data in the dataset are based on the estimates and are subject to sampling variability and thus a margin of error. Neilsberg Research recommends using caution when presening these estimates in your research.

Custom data

If you do need custom data for any of your research project, report or presentation, you can contact our research staff at research@neilsberg.com for a feasibility of a custom tabulation on a fee-for-service basis.

Inspiration

Neilsberg Research Team curates, analyze and publishes demographics and economic data from a variety of public and proprietary sources, each of which often includes multiple surveys and programs. The large majority of Neilsberg Research aggregated datasets and insights is made available for free download at https://www.neilsberg.com/research/.

Recommended for further research

This dataset is a part of the main dataset for O Brien County Population by Age. You can refer the same here

O Brien County, IA Population Pyramid Dataset: Age Groups, Male and Female Population, and Total Population for Demographics Analysis
Last updated September 16, 2023
ACS
Free
Neilsberg
CSV, JSON
2017-2021
CC BY 4.0
About this dataset

Context

The dataset tabulates the data for the O Brien County, IA population pyramid, which represents the O Brien County population distribution across age and gender, using estimates from the U.S. Census Bureau American Community Survey 5-Year estimates. It lists the male and female population for each age group, along with the total population for those age groups. Higher numbers at the bottom of the table suggest population growth, whereas higher numbers at the top indicate declining birth rates. Furthermore, the dataset can be utilized to understand the youth dependency ratio, old-age dependency ratio, total dependency ratio, and potential support ratio.

Key observations

  • Youth dependency ratio, which is the number of children aged 0-14 per 100 persons aged 15-64, for O Brien County, IA, is 33.3.
  • Old-age dependency ratio, which is the number of persons aged 65 or over per 100 persons aged 15-64, for O Brien County, IA, is 33.9.
  • Total dependency ratio for O Brien County, IA is 67.3.
  • Potential support ratio, which is the number of youth (working age population) per elderly, for O Brien County, IA is 2.9.

O Brien County population pyramid

Content

When available, the data consists of estimates from the U.S. Census Bureau American Community Survey (ACS) 2017-2021 5-Year Estimates.

Age groups:

  • Under 5 years
  • 5 to 9 years
  • 10 to 14 years
  • 15 to 19 years
  • 20 to 24 years
  • 25 to 29 years
  • 30 to 34 years
  • 35 to 39 years
  • 40 to 44 years
  • 45 to 49 years
  • 50 to 54 years
  • 55 to 59 years
  • 60 to 64 years
  • 65 to 69 years
  • 70 to 74 years
  • 75 to 79 years
  • 80 to 84 years
  • 85 years and over

Variables / Data Columns

  • Age Group: This column displays the age group for the O Brien County population analysis. Total expected values are 18 and are define above in the age groups section.
  • Population (Male): The male population in the O Brien County for the selected age group is shown in the following column.
  • Population (Female): The female population in the O Brien County for the selected age group is shown in the following column.
  • Total Population: The total population of the O Brien County for the selected age group is shown in the following column.

Good to know

Margin of Error

Data in the dataset are based on the estimates and are subject to sampling variability and thus a margin of error. Neilsberg Research recommends using caution when presening these estimates in your research.

Custom data

If you do need custom data for any of your research project, report or presentation, you can contact our research staff at research@neilsberg.com for a feasibility of a custom tabulation on a fee-for-service basis.

Inspiration

Neilsberg Research Team curates, analyze and publishes demographics and economic data from a variety of public and proprietary sources, each of which often includes multiple surveys and programs. The large majority of Neilsberg Research aggregated datasets and insights is made available for free download at https://www.neilsberg.com/research/.

Recommended for further research

This dataset is a part of the main dataset for O Brien County Population by Age. You can refer the same here

If you're looking for datasets from another year, please feel free to contact us at research@neilsberg.com and we'll be happy to assist you further.

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Population of places that contain O Brien County

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Neilsberg Research team are data scientists with expertise in processing, analysis and visualization of big data helping small businesses make right decisions.

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