Going back a bit...
In unit sales, APS-C vastly exceeds everything larger put together - even Fuji's upper-end APS-C is a relatively small piece of the market. APS-C (including Micro 43) is somewhere between 3/4 and 4/5 of ILC sales (something like 7.5-8 million units/year). The vast majority of these are inexpensive "Best Buy cameras", for which no additional lens is ever purchased (they're used with the 1-2 lenses they came with).
Of these, somewhere between 500,000 and 750,000 are Fujis with a much higher average value per unit than most other APS-C cameras - and many of those Fuji shooters buy lenses. A few more are other higher-end APS-C cameras, although a serial number reporting site estimates total Nikon D500 sales over 3+ years as only 110,000+, compared to millions per model of the D3xxx and D5xxx series. I'd be surprised if the Canon 7D mkII or the Sony A6500 were selling in a completely different order of magnitude from the 30,000-40,000 D500s per year. Most $1000+ APS-C is Fuji...
Full frame is probably somewhere around 2 million cameras per year (this figure plus or minus 20% keeps showing up different places), at much higher unit prices (probably not 4x the price per unit, but maybe not far off, especially if you include lenses). Many or most FF shooters own several lenses for their system, and some own lenses worth much more than the camera body.
I'd be shocked if medium format is even 100,000 cameras/year - it may now be close to that, with the Fujis selling much more than the body/back systems ever did. Average selling price is very high.
BUT
Non-Fuji APS-C almost certainly has an average price/camera kit (body plus lenses owned) well under $800 ($600?)
Fuji APS-C is probably $1500-$2000 (body and a couple of lenses)?
Full-frame is at least $2000, probably significantly higher - depends on lens sales - how many of those cameras share a bag with an expensive lens or two?
Is medium format $10,000 or so per kit? Most of the market is under or around that, but there's Phase and the H system getting towards $50,000/system.
Total revenue from full-frame is probably approaching total revenue from APS-C (especially if you count Fuji X-T, X-H and X-Pro as competing with full-frame, not with $400 cameras). Total profit from full-frame may even be higher than APS-C, because the margins are higher.
Medium format is much smaller, but not insignificant - 1/20 the sales of full-frame, but at 5x the price? 1/4 the revenue???