I don't know if anyone outside of NCEES has been keeping a tracking spreadsheet for it over the years.
There is a separate thread in every results sub-forum that gives the pass rates for every exam in that session. You or anyone else, are more than welcome to compile a master list of pass rates over time for each exam and share it with the forum.
The major-exam pass rates don't vary too much with time. The minor-exams can have big swings because there are less takers. Generally speaking the CBTs have a higher pass rate than the previous P&P exam average.
I wouldn't waste my time trying to map pass rates and perceived cut scores to a given session. Again: not enough reporting to actually know what the cut score (read: highest fail score, assuming it was reported truthfully) was for a given exam. And I'm sure when one does a proper uncertainty analysis that any correlation will fall within the confidence interval.