As far as I know no one has ever been killed on a coaster, like someone being shot while riding. There have been fatalities resulting from rollercoaster's. Although even I don't care to know or think about these things, the question is reasonable, although worded wrong. (death and killed?)
I did research and wrote articles on coaster safety for a school newspaper, and at one time I had the 1998 report, which is published annually by the CPSC ,but I can't find that. I did find the 1995 report so here are some things from that.
From 1973-94 a total of 24 non-occupational fatalities occurred on a Rollercoaster site.
This means the average is a little over 1 a year, but over time it has risen closer to 2 a year with the addition of more coaster's and of course that bad week during September of 99. Still, that is extremely good and is much, much lower than other activities such as driving a car. The chance of you getting hurt while staring at these words (from violent crime, natural disaster's, etc.) are far greater than riding a coaster. Still more important, the rider is likely the problem in most cases, not the ride.
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Joe
*** This post was edited by Joe E. on 2/3/2001. ***