Everybody should know that number of inhabitants is an integer. In case somebody has forgotten it is explicitely recalled in the description by : (** number of inhabitants is an integer **).

When I print the inputs, it only shows up for the test cases I got right and not for the one(s) I got wrong.

Wrong. With your printing you got:

1000
2.0
50
1214
3 should equal 4

which clearly shows the parameters, your result and the expected result.
I understand your frustration for having passed a lot of time in a simple 7 kyu kata but I confirm that "iT's nOt a KaTa iSSuE" and "tHoUsAnDs oF pEoPLe DiD iT jUsT FiNe BeFoRe yOu iN yOuR LaNguAgE.":-)
Cheers and good luck in coding.

See the example in the description, at the end of the third year you already have 1213. Percent is 2, not 0.02 in that test.

I quess that there is smth wrong with the test, cause with parameters p0=1000, percent=0.02, aug=50 and p=1214 the right answer must be 5, but expected 4. I even tried to calculate it manually, and got that if we spent 4 years then we will get 1200,8 with is less than 1214. Could someone help me with it?