Does anyone have any stats on the rate of mass murders per capita in the US over time?

Mass murders are actually extremely rare.

According to the US census of 2000, no gender or ethnic group had higher than a 6/10 of a per cent chance of dying from homicide of any kind.

Black males were the only exception, and they have about a 5% chance.

According to the Statistics murders are decreasing on the per capita basis and have been for 30 years.

I don't know about mass murders, but I have read that the number of incidents of violence in schools (I think this was secondary schools, not college) have been decreasing over time per capita. BUT, when incidents do occur, they have been getting more likely to include fatalities because they are more likely to involve guns.

When you start trusting everything Wikipedia states, you are in trouble. I can go on there and change anything that I wish to. That's how reliable Wikipedia is! Besides, many own some type of weapon either with them or at home. You should also bear in mind what Rayne Storm has stated.

here's a graph showning the rate over about 50 years

i dunno