222 years ago - On this date in history

according to Posted History at "Writer's Almanac" (American Public Media: Garrison Keillor)

On August 2 in 1790, the first U.S. Census was conducted. The United States was the first country in the world to make a census mandatory in its constitution. It is to be held every 10 years and to serve as the basis for Congressional seats, electoral votes, and to aid planning of government services. In 1790, only the names of the heads of households were recorded and the number of "free white males" were counted for draft purposes. Women were not allowed to work as census takers and were rarely named in the census except when widowed. Genders and ethnicities of all other residents were noted, but slaves were only counted as three-fifths of a person, and American Indians were not counted at all.
It wasn't accurate, but the first census recorded just under 4 million people residing in the United States. In 2010, almost 310 million residents were recorded. It is now the largest peacetime operation in the country and employs more than a million Americans.