While I was over at my sister-in-law’s house Sunday night, I happened to notice a stack of old comics on the coffee table and picked up this one—Detective Comics #350 (April 1966)—because who could resist a Batman drawn by Joe Kubert or those Go-Go Checks?

The house ads in the issue were as much fun as the stories (which is often the case), and I was particularly intrigued by this one, in which DC claimed it sold “twice as many comics as any other competitor” and “almost as many as all other comics combined.”

Which had me thinking—how long has it been since DC could claim it was on top? I’m not sure, but as this chart from Newsarama shows—it depicts the April 2013 comic book market share—things have changed quite a bit in the intervening 47 years.

So does anyone know exactly which year Marvel overtook DC? Was it Spider-Man related? X-Men related? My Google-fu has failed me this time around and doesn’t seem to be coming up with the answer.