Dates in AP Format In addition, never use an apostrophe when writing about a decade or century. The only time an apostrophe is required is when referring to a decade and omitting the first half of the figure ('80s). Otherwise, follow these guidelines: b. 1960-1989 - Use hyphens instead of apostrophes for decades. C. 1990 and later - Leave out the hyphens and begin with "1990's." Alternatively, if using digital technology, start with "In 1990," or simply "In '90." Before 1990 - Use apostrophes to indicate years before 1960 or after 1979. For example, if making reference to the 1920s, use an apostrophe because the decade begins with 0 rather than 1. If referencing the 1950s, however, there are no years between 1945 and 1959 that need to be written with an apostrophe so you can say "the 1950's without putting yourself at risk of being labeled as inaccurate or outdated. All other times - Leave them out entirely unless necessary for clarity reasons. So, for example, if wanting to mention that John Lennon was born in 1940 but died in 1980, you would not need to include any apostrophes in your article because it is obvious from the context what decade he belongs to.