Don’t get confused guys.
Numerator shows the visited days which keeps changing according to your visits while denominator shows a constant value i.e. 100
That is why it is so much confusing.

So what should it show
It should show the percentage of visited days.
Using this formula:

So mine would be 51 / 150 * 100 = 76,5? But this would mean I achieved already 76,5 % of the whole requirement, and this means the requirement is equal to 66,666… days which isn’t possible.

Koders, this is confusing, just be patient and the staff will add you if you meet the requirements. Also, remember, reaching TL3 does not mean that you will become a ProKoder.