Do years need apostrophes?

Q. When I am writing about plural years, do I use an apostrophe? Where does it go?

Adam answers:

The answer to this depends on how exactly you are using the years in question. Here are the rules:

  • No apostrophe if you are talking about the years of a decade — “In the 1990s” is correct, “In the 1990’s” is incorrect.
  • If you are showing possession, use an apostrophe: “2014’s first baby was born at 12:01 AM.”
  • If you are shortening a year or decade, you use an apostrophe to replace the first two numbers of the year or years: “I wish I grew up in the ’60s.” or “I finished high school in ’08.”
  • As for the word “years” — If you are talking about more than one year, the plural of year is spelled “years”. The only time you would use “year’s” is to show possession of something: “The year’s hottest day was in July.”