Therefore "more or less" ;) of course I didn't make a study on it, just traveled a bunch of countries and only in thosei noticed it... Needing to add that this is not something that would jump in my eye first time I visit a county.

On a side note: in Germany, we use the -2, -1, 0, 1, 2 scheme, bit most of the times they write it more clear with: 1. OG (first upper floor), EG (ground floor), 1. UG (First lower floor). I think "upper" and "lower" is not a good translation, but I'm now to tired to think of someone better suiting