Answer:
The population of the colonies that later became the United States increased steadily in the decades prior to , and including, the American revolution. The first decennial census took place in 1790 . Since that time, the natural increase, i.e, the excess of births over deaths, has been a constant contributor to popular growth. The other factor, immigration, has ranged for negligible to large at various points in the nation's history.
After 1830, immigration began to grow again. Although the birth rate showed a decline , the net population growth rate remained high until after the Civil War. In the decade ending 1870, population growth dropped below 30% for the first time in the nation's history. Substantial immigration kept the population rising at 20% or more for each decade until 1920, when the effect of Word War I reduced it to 14.9% .
