Previously, I asked a question about whether I should omit the article, "the" before the late 80s.
I saw in the answer by Absolute Beginner that he writes '80s for Eighties, the apostrophe is added before the numeral, i.e. 80s. Lawrence C put the apostrophe in between, i.e. 80's.
The answers have made me very confused, could you tell me which is the correct numeral for the years 1980, 1981, 1982... 1989:
80's, or '80s, or 80s ?
I always write 80s, does it mean that I am wrong?