From "It's Only A Game...Or Is It?", Moira Johnston,
New West, August 25, 1980:
"Gygax, a former shoe-repairman, insurance underwriter, unpublished novelist and unemployed gaming enthusiast, describes the phenomenal growth of D&D. 'In 1979 we sold a quarter of a million copies of the basic D&D set, a little better than double over 1978. Our gross sales volume has gone from $150,000 in 1975 to $2.5 million in 1979. We expect to double or triple everything this year.' Although
FRP games still rank behind electronic games in national popularity, 'D&D is now equal to any boardgame, including Monopoly', says Dana Lombardy, whose games column in Virginia-based
Model Retailer magazine has closely monitored the rise of D&D and
FRP. The most stunning measure of growth, Lombardy reports, is that 'of a total national
FRP games market of $20 million in 1980, TSR will account for more than $5 million of that - at least 25 percent!'
FRP wasn't even listed as a games category in 1974."
This is pretty interesting stuff. Gygax is being specific in this article for a real reporter writing for a mass-market audience. His in-house numbers roughly match up with what MR was reporting as well, though their estimate of TSR's market share seems a little low to me.