Well....
Video Game Chartz has no sales figures for how many were shipped. For whatever it's worth, Wikipedia
says "Following its release, Turtles in Time became Konami's best-selling arcade title.[27] In the United States, the home console conversion was the top-selling Super NES game in September 1992."
Wikipedia also says "As of 1993, the first eleven TMNT video games had sold 18 million units worldwide, earning nearly $450 million in sales revenue." So that is fairly telling at least because Turtles In Time would fall under that banner somewhere in the 18 million copies sold across all TMNT games up until that point.