I just happened to see this article/website while listening to a "70s hits" channel at the hotel I'm staying.

Have you ever considered analyzing the hit progressions thru time, to see if and how our tastes change?

Also, using a self-generated formula that a hit song is probably 25% root progression, 25% melody over that progression (the hooks), and 50% lyrical content...I wonder if some attempt at integrating all three of those items could yield fruitful, interesting results.

Great work, BTW...as a lifelong musician/songwriter, I enjoy sites like yours to help gain a deeper understanding about how professionals manipulate the sonic palette to craft songs and interesting melodies.