Spotify's Insights blog took to the streaming service's massive music Catalogue with the intent of figuring out what Keys were Most Popular among the 30 Million tracks. Every Song is based around one of 12 possible **tes, as well as a mode (generally major for "happier" music and mi**r for "sad"). That results in nearly every piece of Western music being played in one of 24 possible keys. Jazz pianist Kenny Ning moonlights as a data analyst for Spotify and he charted the results of what he found. So what key was Most popular?