Sick days are not “offered” by employers. Sick days are prescribed by the doctors and there is no upper limit. After all, your sickness will not disappear just because it has been N days. That's at last how it is in Poland.
And there's an unlimited number of sick days. As long as you have a doctor's note, you still get paid, up to some ridiculous limit at which you might have to get government support instead.
Many countries have this system and the usual effect is that the duration people are sick for is magically never less than 2 days. It's dumb policy.