The drop was accompanied by a 4.6 percent drop in property crime, marking the seventh consecutive year that nonviolent crime has dropped. The figures challenge theories among some criminal analysts that crime tends to rise in times of uncertain economies.

The trend is “one of these welcome puzzles,’’ said Richard Rosenfeld, president of the American Society of Criminology. “This is forcing us to think more seriously under what conditions economic activity influences crime.’’

In the 1970s and early 1980s, when the economy went south, crime rates went up. Inflation was high then, which could account for the different reaction.

James Alan Fox, a criminologist at Northeastern University, said that although the downward trend is encouraging, the economy “could come back to haunt us’’ because of a nearly 10 percent drop per capita in police budgets in the past few years.

“There is a connection between the economy and crime rates, but it’s not that when the economy is bad, people go out and commit crime,’’ said Fox.

“When the economy is bad,’’ he said, “there are budget cuts. Less is spent on youth crime prevention and crime control on the street.’’

Each of the violent crime categories decreased from 2008, as did each of the property crime categories.