Washington, D.C. ? Violent crime is down for the third straight year. Property crime for the seventh. But why?

Experts are hard-pressed to come up with an explanation.

Violent crimes reported to police dropped 5.3 percent last year, the FBI said Monday, and reported property crimes fell 4.6 percent.

So explain this: Police budgets have been shrinking. Not only that, typically crime rates head up when the economy heads down.

Among the theories: As overall economic activity slows, more people who otherwise would be at work are unemployed and at home, and when they do travel they are not as likely to carry items of value, so burglaries and street robberies decline.