The velocity of money, the number of times a dollar is exchanged, isn't a perfect indicator of economic health, as it sometimes correlates with inflation. But it is a good one. You see, in a booming economy, a dollar is exchanged frequently. In a economic depression, a dollar is exchanged infrequently. Thus, it would be of great concern if velocity dropped to Great Depression levels. Well, velocity never stopped declining since the beginning of the Great Recession, and it recently dropped lower than its lowest point during the Great Depression.