1930s: The U.S. economy suffers from a crippling economic depression. Older industries, such as the automotive, railroad, steel, textiles, and agriculture, are stagnant. New, service-based industries hold promise for economic development, but low wages and extremely high unemployment delay their growth. The national income is cut in half between the stock market crash (1929) and 1932.

1990s: The country enjoys the longest period of economic growth in history. The Dow Jones Industrial Average breaks the ten-thousand mark for the first time. Unemployment is at a record low. A booming high-tech industry fuels the economy, leading to higher wages and more disposable income. This, in turn, supports a service-based consumer economy. Despite prosperity, consumer debt is at a record high. The average family spends more than it earns in a given year.

1930s: The average family income in the United States is in the range of...