Really good article pertinent to all games including alteil.
Rarity and Power: Balance in Collectible Object Games
site has lots of other great articles on games
Also inside the TCG business 20120:
Trading Card Game Industry
From the T to the C to the G
Some very interesting graphs and tables in figure above with major tcgs, market share, average price for a rare...
I would guess that alteil has less than 0.1% of the market share for tcgs which is in itself generous. Also guide seems to be only referring to paper tcgs. Many tcgs have online versions now and most tcgs are online so it is a bit outdated
Feel free to read or browse though and I would be greatful for any comments