Why The Decrease In Crime?

The crime rate in the U.S. has been falling. People are asking: Why the drop?

Several possible explanations are given. This one makes the most sense to me:

The baby boomers grew up. With birth rates peaking between 1957 and 1961, the proportion of men in the US in their late teens and early 20s was highest in the late 70s and early 80s. As time went on, the proportion of people at "criminal age" decrease.