Because people in the POLL thread were talking about it, I decided to run a script to recalculate the level distribution on here again (or at least the distribution of everyone with the Basic badge, but that should be almost everyone who ever visited the forums). The results can be found in this spreadsheet.
I also made a few graphs to visualize the data a bit better.
The distribution itself doesn’t seem all that much different from the one @Kumirei found last year. Still a big drop at the start, and a small spike at level 60 where everyone who cleared at the levels accumulates.
Here’s the same plot but with the y-axis on a logarithmic scale.
So it’s close to an exponential decrease in the number of users per level, with a large drop after the free levels are over and a spike at level 60.