The United States at the time of the Revolution was a country of young people. Without a hereditary aristocracy, the 2.5 million scattered settlers, mostly farmers, who made up the country at that time, relied on whoever had the energy to get the job done. Jefferson was only 33 when he wrote the Declaration of Independence, and Washington was 43 when he took command of the Continental Army. The 56 delegates to the Continental Congress weren't necessarily the richest men in America; the truly rich mostly stayed loyal to the King. The early Congressmen in 1775 showed how mobile people in America already were — more than a quarter of them had lived in two or more states.
At the time of the Revolution, about 60 percent of Americans were from England with the next biggest groups being African slaves at 15 percent, the Scotch-Irish at 8 percent, and Germans at 7 percent. The California Gold Rush of 1849 populated the West Coast almost overnight with the first 100,000 Americans settlers. Average Americans lived longer at the time of the Revolution than they did during early heavy industrialization a hundred years later in 1890.
As the U.S. developed, the percent of residents who had been born in other countries grew from 1 percent in 1810 to 14 percent after the Civil War. This jump had an unsettling effect, but it also provided manpower for the North in the conflict with the South and people to work in the new industries after the war. Bad harvests and revolutionary unrest drove people out of Europe, and family ties with earlier immigrants pulled them in to the U.S. Currently, 12 percent of the population of the United States is foreign born.
The U.S. moved from being a prosperous-but-small farming nation at the time of the Revolution to the dominant international economic power with a quarter of the world's money in the early 2000s. Early colonies didn't work out as investments for absentee British investors, who subsequently turned them over to the people who lived here. Colonists learned to support themselves quite well; by the time of the Revolution, average American living standards were better than the ones in England. That gave them something to fight for.
Between 1920 and 1985, the U.S. lived through three depressions and six recessions lasting a total of 12 years during that 65-year period. With minor recessions, the U.S. economy was growing about 75 percent of the time and in decline about 25 percent of the time in the 1900s. The Great Depression of the 1930s was by far the worst, lasting almost six years and continuing until World War II. A recession starting in 2008 has lasted for four years.
Although the United States has experienced bad economic times, its general growth has been good through the end of slavery, the Industrial Revolution, and the postindustrial information society.