The one spike in the MICKEY MOUSE AND FRIENDS graph indicates the switchover from MM&F to WIZARDS OF MICKEY. WOM #2 sold about 1300 copies less than WOM #1, which might be due to the "collector's item" reflex but is still bothersome given that MM&F and WOM have been telling a continuing story.
Kneon includes links to some information on Gemstone sales as well. Boom! appears to be holding its own reasonably well relative to Gemstone's later sales figures, but the downward trend is nonetheless worrisome. I'm especially disappointed in the figures that Kneon reported for the hardback and softcover collections. The first volume of LIFE AND TIMES OF SCROOGE McDUCK barely cleared the 1000-copy mark, and it's the only collection to have done so to date. WALT DISNEY'S VALENTINE CLASSICS scored a paltry 383 copies, a real shame given the high quality of that collection. MICKEY MOUSE CLASSICS did better (785), but only slightly better than CHRISTMAS CLASSICS. Hopefully, bookstore sales will help pump up these figures a bit, especially on the collections that merely reprint material that has already appeared in the monthly titles.