Level 20 skill gems seem a bit too rare

I have well over 15 days played and 3.6 million monsters killed with almost all of those being in level 80-83 maps. A conservative estimate is that I average 6-7 divines per day in raw currency drops putting me somewhere at around 120-150 raw divines in the last three weeks.

Today I found my first level 20 gem from a level 80 zone boss, which i think makes him 82 if the formula is the same as 1.

I think this is far too rare.

At last I now know they could posible drob from level 82 monsters :). Wasn't sure if I had to run corrupted T16 boss elevated maps to get one. Or even a T16 corrupt elevated pinakle boss.