The largest waves of increased inflation rates during the 20th century occurred after World War I and World War II. Another major increase in inflation happened from 1970 until the early '80s.
Inflation is usually less during times of recession when employment is low and the demand for goods falls. When the economy is strong and consumerism is at an all-time high, the rate of inflation tends to rise. Hyperinflation occurs during a sudden burst of inflation. Although other countries, including Russia, have experienced hyperinflation, the closest the United States has come to hyperinflation was in the Confederate States during the Civil War.