In 2005, Billboard changed its methodology to include digital downloads, and in 2007, it included digital streaming. In 2013, they added video streaming from sites like YouTube. There’s certainly a correlation between the music industry’s digitization, and women’s drop in representation. In 2016, only 22 percent of popular songs were performed by only women. That’s a huge drop from the 41.4 percent that women performed in the decade 1997-2007.