quick look at the sheer number of accidents in the eighties shows why
It is indeed interesting that the accident rates were so high in the eighties (though possibly even higher in the seventies?). Would anybody like to debate why the accident rates fell in the nineties and have fallen very considerably this decade?
After a rough perusal of the reports, it would appear that pilot error was a more significant factor in the eighties than it is more recently. Also, the Harrier seemed to be particularly accident prone in the eighties. Of course, without data on number of hours flown across the decades it is not possible to make definite conclusions, but my gut feeling is that pilot error rates are down and aircraft reliability up since the eighties.