This is basically thirty year old news. Harry Hurt, a professor in a Southern California college, did a study of motorcycle accidents back in the late 1970's and found that 70% of all fatalities are from riders on "new" (they haven't ridden it before) motorcycles. The danger fell dramatically after the first 90 days. So if you're going to get killed, it will be on that new bike you bought this spring, before July. After that, ride like an idiot. :-)
He also found that 90% of fatalities were from head injuries, the same percentage as in cars (THERE, you "donor-cycle / murder-cycle" haters).
I'm quoting these numbers from memory, so if you google "Harry Hurt motorcycle fatalities" and I'm wrong, don't beat me up. I didn't have the time to check out every link this morning.