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Like many major American cities, Boston has seen a great reduction in violent crime since the early 1990s. Boston's low crime rate since the 1990s has been credited to the Boston Police Department's collaboration with neighborhood groups and church parishes to prevent youths from joining gangs, as well as involvement from the United States Attorney and District Attorney's offices. This helped lead in part to what has been touted as the "Boston Miracle". Murders in the city dropped from 152 in 1990 (for a murder rate of 26.5 per 100,000 people) to just 31—not one of them a juvenile—in 1999 (for a murder rate of 5.26 per 100,000).

The Boston Miracle is the name for the reduction in what crime from 1990 to 1999?
Murders