An interesting statistic:
When the Declaration of Independence was signed on 4th of July 1776, there were an estimated 2.5 million people living in the newly independent nation (http://www2.census.gov/prod2/statcomp/documents/HistoricalStatisticsoftheUnitedStates1789-1945.pdf), today, the census is counting an estimated 313.9 million people (http://www.census.gov/main/www/popclock.html).
Happy Birthday America!