Close enough (for the higher ones at least).
A good barometer is seeing what AI levels are for Very Easy, Easy, Medium, Hard, Very Hard are in Custom.
Career levels are roughly in the middle of each of these difficulty bands (so Masters would be about 95%), with some variance based on a number of factors (which AI is driving, conditions, car, location etc.).
100% AI difficulty is roughly (to my knowledge and from my experience of doing Career/Historics), less than 5% off human world record pace.
In short: if you're competitive against the highest AI number in each band in Custom, you should (provided you don't make too many mistakes) beat the similar band in Career.