How many people alive from a specific time period?

I’m trying to get a rough estimate of the number of people alive today in the US who were at least 14 years old in the years 1975-1980, but I’m having a hard time figuring out how to do it.

So I need:

–US population 14 & over in 1975
–Plus everyone who turned 14 in each year of 1976-1980
–minus everyone from that total who’ve died.

Help!

The US Census doesn’t have a calculator that works like this, or any calculator at all that I could see.

So what you’re asking is how many people are over the age of 50? Census data generally trails behind a bit since it takes some time to collect the data, but in 2014 there were 108.7 million Americans aged 50+. http://blog.aarp.org/2014/05/14/top-10-demographics-interests-facts-about-americans-age-50/

If I’m reading your question properly, you don’t need all that information to get your answer.

On July 1, 2015, everyone alive that’s 49 or older and roughly 1/2 of the 48-year-olds would have been 14+ at some point in 1975-1980. Open this file in your favorite spreadsheet program; it’s got the most recent population estimates for the US (as of the aforementioned 7/1/15, column J) broken down by age (column A) and sex (column B: 0=all, 1=M, 2=F).

Half the 48-year-olds + everyone older = 117,164,384 people.

Thanks guys–both for the answers and for giving me the simpler ways to think about it.