FWIW, upon review of historical records (so to speak), it looks like my estimate of “5-10” as a typical number is being heavily affected by the earlier years of his lists, which makes sense, as I have had decades now to subsequently happen upon and buy some of those which I may not have been aware of at the time they came out (or, to be fair, I might not have been able to afford at the time).
For more recent years, it’s been more like 3-6 that I own and another couple that I’m already aware of and interested in.