You may laugh Blair, but I have no data for years that recent. I've been collecting price info for older ones. 1960s and earlier.
Trans Stamps 22" average $650 n=4
Large Stamps 22" average $270 n=25
Small Stamps 22" average $227 n=5
60s Stamps 22" average $221 n=6
Given my sample sizes the Large Stamp estimate is the only one which I'd trust as having reached stability. More data to collect.
So all I can say is this pattern of lower expected prices as they get more recent holds across the different diameters. I've recorded prices on a number of 70s and later 14" hats (because of my New Beat project) but those won't help either.
You could see what eBay completed sales has on offer, but one of the reasons I stopped at the end of the 1960s is that once you get into the late 70s and later sellers seem to stop giving much effort to detailed information. That plus I'm just rather busy with the amount of data collection I already do...what with old Ks, Avedis, North American Ks, 602s, and Sound Creations. Not to mention trying to sort out timelines and document things properly.