What percentage of offensive success is based on successfully executing a game plan vs. the defensive failing to execute theirs?

Basically, how often does a play work because the offensive is doing something right and how often is it because the defensive is doing something wrong?

(Which can get a bit fuzzy when lots of plays are designed to fool the defensive into making the wrong reactions, play-action passes and counters and such, but even throwing those out, I still think the answer would be fascinating.)