Thought we were talking about engines
But top causes of helicopter accidents :
Mishandled Controls
(22.02%) 85
Drivetrain Failure
(4.66%) 18
Wire Strike
(4.40%) 17
Under Investigation
(3.89%) 15
Loss Of Control IMC
(3.63%) 14
Maintenance Error
(3.11%) 12
Collision with Ground Based Object
(2.85%) 11
I noticed you stopped just before:-
Engine Power Loss or Variation
(2.59%) 10
Engine Failure
(2.33%) 9
Which is almost 5% of events.
Also, that list is referring to "accidents" rather than "crashes". There is a difference i.e a wheels up landing following undercarriage selection problems is listed as an accident as is a cement bag blowing into the MR head after landing but they are not "crashes". Perhaps if a list of crashes were to be compiled, engine failure would be higher up.