Basically meaningless report. WHY have the number of fatal crashes dropped? It would be good to know how many riders there were each of those years, and how many miles were ridden. What if the decrease is strictly due to fewer people riding and the remaining people riding less? Less exposure to a hazard is very likely to reduce the incidence rate.
I've seen similar feel good reports for other forms of vehicular crashes and fatalities that showed big improvements in some states back during the depth of the Great Recession. All sorts of public safety officials were quick to take credit for the improvements, but of course the real "culprit" was the lousy economy that left many people not commuting to a job, unable to afford road trips and vacations, and possibly even making folks cut back on excessive drinking before driving.
The part I do believe is that over half of all fatal motorcycle accidents are caused by the motorcyclist. Around here there are many more single vehicle crashes than the "car turns in front of the motorcycle" crash that many bikers like to cite. Drinking and riding is a big factor in those single vehicle crashes, at least the ones reported around here.
Jerry