# How many people lived in the U.S. between 1974 and 2004?March 20, 2012 8:03 AM   Subscribe

[MathFilter] How many people were alive in the U.S. between 1974 and 2004?

I am looking to find out how many unique individuals were alive in the U.S. between 1974 and 2004. So that would include a person who died on January 1, 1974 and a baby born on December 31, 2004. Is there a way to calculate this number given available data? Does the issue of immigration and emigration foreclose the possiblity of reliable data?
posted by arveale to Society & Culture (11 answers total) 1 user marked this as a favorite

No, you can't get an exact number for this. But since you want unique individuals that lived in the US between those dates, one way to get an estimate is to get the population in 1974, add all the births each year, and add all the immigration numbers for each year. You can exclude deaths and emmigration because those people all lived in the US at one point in your time frame and are included in either the initial population, the births, or the immigration figures.

The reason you won't get exact numbers is due to many factors, including illegal immigrants, unreported births, census inaccuracies, etc.
posted by Grither at 8:10 AM on March 20, 2012

I just yesterday ran across this awesome JavaScript technology demo on U.S. population numbers, which says it pulls its data from the Minnesota Population Center.

That looks like it will at the very least give you demographic slices in 5 year age groups, you can presumably get a fairly accurate look by stepping through that data set and dropping the ones who were alive in the previous segment. You'd obviously have to do some looking at immigration patterns to normalize for that, but dig deeper into the data, the folks at MPC/IPUMS may have already done that for you.
posted by straw at 8:12 AM on March 20, 2012

What you need is
1) Number of people in the US in 1974.
You can get this from the Census but it wont be accurate enough to tell you how many people there were on a specific day.

2) Births from 1974-2004
You can get this from many places include the Department Health & Human Services or Statistical Abstracts.

3) Immigration into the US
You can get this from government records as well.

You don't care about deaths or emigration since those people have already been counted. Also you have to assume that someone who emigrated is not immigrating back.

posted by vacapinta at 8:12 AM on March 20, 2012

Also, I hope you aren't including tourists because that throws your number up significantly. Are you? I assume you mean US citizens and residents.
posted by vacapinta at 8:18 AM on March 20, 2012

Yeah, citizens and residents. Having just run a (very) rough estimate, it seems to be in the 350-400 million range.
posted by arveale at 8:23 AM on March 20, 2012

I wonder if this is a way to do it too.
posted by emelenjr at 8:39 AM on March 20, 2012

I'm not sure if the above methods are going to account for US citizens who were living abroad in 1974 and subsequently returned, should you care about that level of accuracy.

I would assume those people don't get counted in either immigration data, or a snapshot of people resident in the US at any given point in time.
posted by philipy at 8:43 AM on March 20, 2012

You don't need to count births. You just need the population of the final year + the death counts for all years in the series. If someone died in the measured period they were also alive for part of the measured period.
posted by w0mbat at 11:22 AM on March 20, 2012

w0mbat's method would omit people alive in the earlier years who moved out of the country. So you'd have to count both deaths and emigration counts back to 1974.
posted by beagle at 12:01 PM on March 20, 2012

No beagle, you don't have to subtract emigrants. People who left the country in the period were also living in the country for part of the period.
posted by w0mbat at 12:13 PM on March 20, 2012

Oh never mind, I see what you mean. You need to add emigrants for all period years because they would not otherwise be counted.
posted by w0mbat at 12:16 PM on March 20, 2012

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