[baddox]

I find it hard to believe that D major wasn't one of the more common chords to follow and E minor.

[Goladus]

Note that he's only searching songs written in C Major. A D Major would be outside the key so naturally it would be quite rare.

The results are exactly as I would expect. F is the most common chord to follow E, because that's the primary way to resolve the dissonance of that note in C major. When E appears in other chords in C Major it will also tend to resolve to F unless there's a good reason not to (cadential 6-4).

A minor is the next most common after F, because that's the next step in a descending circle of 5ths pattern (E, A, D, G, C)

[baddox]

Ah, I missed that the graph was only showing songs in C major.

[wildwood]

Why would the II chord follow iii? Can you cite some examples of that?

The only pop/rock use of II that I can think of is as a turn to drive II7 -> V7 -> I.

[HTryan]

Exactly. D Major chord is a V/V in C Major, which has only a couple of common uses in popular music according to the Hooktheory database. V/V -> V7 -> I is one common one. Another is a substitution for ii, like: I -> V/V -> IV -> V, see John mayer, Kelly Clarkson, Kenny Chesney etc.

[Goladus]

I agree, I'd really be interested to see what sort of pattern he's thinking about.

[baddox]

I missed that the graph was only showing songs in C major.

[minitrollster]

I tend to agree, but when you think of it, D major isn't used that much in popular music. When you talk about country or acoustic guitar, sure, but not so much in the Billboard charts.

[deadhead]

The graph showing the chords following E minor was created after all songs were transposed to the key of C major.