The average song length on the Billboard Hot 100 chart is now 20 seconds shorter than it was five years ago, clocking in at three minutes, 30 seconds.

It has nothing to do with artists having less to say or complex focus groups showing shorter audience attention spans. Blame it all on streaming music services.

Such services like Spotify, and Apple Music, were responsible for 75% of the music industry’s overall revenue last year. And they pay on a per-play basis.

This amounts to less than a half cent per play, so artists don’t have an incentive to do long, complex music. In other words, a two-minute song will earn them the same as an eight-minute opus.

Quartz took a look at the average track length on several artists’ recent albums and the trend was fairly universal. Rapper/singer Drake’s average song is 11% shorter on 2018’s Scorpion, compared to 2016’s Views. Kanye West is packing more songs per album as well. And even country artists like Eric Church and Jason Aldean are shortening the length of their songs.

Certainly factors like consumer attention spans could be affecting musician decisions on song length, but the economics of the industry today make it more likely streaming music is to blame.