Terrible sources. Source one and two are for Massachusetts alone in 1990.Source three is an article written in 1986 without sources listed. Source 4 states stats without showing where this data is from. The last source is is an well written article from 1996 however most of its stats (which actually have sources) are based from the late 80’s/early 90’s and was before the MRA were a thing. This is why everyone should be careful with statistics because its very easy to manipulate them for any side.