"Decades", by Randall Munroe, licensed under Creative Commons Attribution-NonCommercial 2.5 License
In the 90s, our variety radio station used the tagline "the best music of the 70s, 80s, and 90s." After 2000, they switched to "the best music of the 80s, 90s, and today." I figured they'd change again in 2010, but it's 2017 and they're still saying "80s, 90s, and today." I hope radio survives long enough for us to find out how they deal with the 2020s.