Who has written the most number one songs in history?

According to the Nashville Songwriters Association International, there are some key ingredients that go into crafting a no. 1 hit song. Those include things like when the pronoun "you" is first used, when the title of the song is included, and the verse/chorus structure.

Which makes it sound like if you just study hard enough, you too can write your own hit song and top the charts. Yet when you look at the list of songwriters who have number ones, it gets pretty damn exclusive. Maybe it's not so easy after all.

Turns out this songwriting thing is kind of hard, especially in terms of the biggest hitmakers. Who has the most number one songwriting credits in music history?

Click START to answer.