Apostrophes
An abbreviation for a specific year or a decade is correctly written as follows: For instance, 1990, abbreviated for the specific year becomes ’90. An indication of the decade of the nineteen nineties (1990s) becomes ‘90s.
The leading apostrophe stands in for the missing numbers and the ess (s) indicates the plural of the years 1990 to 1999. A common but incorrect way of writing this is 90’s. The leading apostrophe is missing which completely changes the meaning of the word and brings up the question “Ninety what?” The apostrophe ess (90’s) changes the plural of the decade of the ‘90s to a singular possessive requiring an object which is, in these cases, always missing.