It comes from Strauss-Howe Generational Theory. Strauss and Howe coined the term "Millennial", so I'll take them at their word for the size of the cohort. Here'

It comes from Strauss-Howe Generational Theory. Strauss and Howe coined the term "Millennial", so I'll take them at their word for the size of the cohort. Here's a table from Neil Howe's website: http://www.lifecourse.com/about/method/timelines/generations.html http://www.lifecourse.com/about/method/timelines/generations... And a Wikipedia article with an overview: https://en.wikipedia.org/wiki/Strauss%E2%80%93Howe_generational_theory https://en.wikipedia.org/wiki/Strauss%E2%80%93Howe_generatio... Source for Strauss and Howe coining "Millennial": http://usatoday30.usatoday.com/money/advertising/story/2012-05-03/naming-the-next-generation/54737518/1 http://usatoday30.usatoday.com/money/advertising/story/2012-... > "No one knows who will name the next generation," says Neil Howe, who, along with his deceased co-author and business partner, William Strauss, is widely credited with naming the Millennials, a generation he figures spans from about 1982 to 2004.