This dataset provides annual population estimates for the State of Iowa, and cities and counties in Iowa. It compiles data from the U.S. Census Bureau, Population Division’s Population Estimates Program (PEP). Data is released in Vintage Series, which contain annual population estimates for every year back to the most recent decennial census. Every time the Census Bureau releases a new "vintage", they do not just add a new year of data. They re-estimate every single year back to the last Decennial Census using updated methodology and more accurate administrative records (like final birth/death certificates).
Where available, Intercensal Estimates, which are the official "final" numbers for that decade are provided to facilitate comparing current annual population estimates to previous decades.