Basically I just need to know the answer to the above question. I think the answer is approximately 125K, but I’m wondering if there’s an exact answer presently known to this. I was trying to estimate the answer using hints from the initial settings on TheoryTrends. We get that (selecting Rel. and Major): 12% of entries have I, 10% have IV, 3% have ii, etc. Selecting chord IV only, we get that there are 12054 entries involving chord IV. Assuming 12054 is 10% of the total, we would calculate 120 540 as the total number of entries. However, we also have that 3% of entries involve ii. Selecting chord ii only, we get that there are 4229 entries involving chord ii. Assuming 4229 is 3% of the total, we get a calculated total of 140 967. I have calculated estimated totals in this way based on chords I, ii, ii7, IV, V, and vi getting an average of about 127 900. This figure doesn’t quite check out however when the percentages are recalculated. This is probably because the percentages are rounded. For example, the 3% for chord ii might actually be more like 3.4% which would bring down the 140 967 estimate considerably. With this in mind, I refined my estimate to 125K. (Confusingly enough, on the database, Hooktheory says it searches though “46532 songs.” So how could there be 125K entries in major alone? I’m guessing the explanation is not all of the entries are considered “songs” in that search.)