Isn’t OP analyzing frequencies of individual chords, not chord progressions?

Analyzing individual chords involves counting the frequency of each chord (such as G, C, or D).

Analyzing chord progressions would involve counting the frequency of chord pairs (such as D—A or C—G), chord triplets (such as D—A—Bm or C—G—Am), or longer sequences of chords. For an alternative look at the data, you could also normalize chord progressions across key signatures for your analysis (D—A or C—G would both normalize as I—V, D—A—Bm or C—G—Am would both normalize as I—V—vi).