[Kunst]

The apostrophe at the other end is correct, though. It signifies something is missing (i.e. The “19” of ‘91). Placing it after the digits (“90’s”) doesn’t make any sense - not even in American English! - which is why I’m surprised it’s so prominent in a package which must have gone through a large amount of signoff.

The amount of people not "knowing" their language is astonishing high, even in the media

I'm Italian, and when translating from English, some people do an awful job by bringing English grammatical/morphological structures into Italian, which at times become popular