But we'll get to that in a second. They have to, because it helps the feds figure out where they need to spend money. The Census takes the count from the last full census and adds the number of people born and the number of immigrants who've come in, and subtracts the number of people who've died. They use existing data such as births, deaths, Federal tax returns, Medicare enrollment, and immigration. You've also probably heard of the Census's population projections.
Projections are different, because they look to the future.
Estimates are based on data we already have. Enough with the jabberjawin', I want to download If you've never downloaded data from the Web into a spreadsheet before, fear not. It's easy and you can do this with data that other agencies put on the Web. If you already know how to do this, then take this time to reflect quietly on past downloading experiences. For this example, we'll use the 1990 to 1997 Annual Time Series of Population Estimates for counties in California.