By Christopher Ingraham, The Washington Post
Arrests for simple marijuana possession in the United States fell to nearly a two-decade low last year, according to new statistics released Monday by the FBI.
The number of arrests for marijuana possession in 2015 — 574,641 — is the lowest number since 1996. It represents a 7 percent year-over-year drop, and roughly a 25 percent drop from the peak of close to 800,000 marijuana possession arrests in 2007.
The FBI data suggest that, in…