It's a shame that we will probably never know the total amount of ColecoVisions sold. They officially passed the 2 million units sold mark in 1983. Despite the North American video game crash, the system remained in production at Coleco until October 1985. But, exact unit sales for 1984 and 1985 are unknown, although extrapolations have been attempted using the $ sales from Coleco's '84 and '85 Annual Reports. It's within the realm of possibility that it managed to surpass the 3 million mark. I've seen 6 million mentioned by a number of people on various forums and articles, but not sure where that figure derives from. It was a great system for it's time, but released to close to the Crash unfortunately. I have a unique attachment to it since it was my first video game system and fostered my lifelong passion for video games.
If we get any higher official figures I'll be sure to make note of that. It is possible we missed some numbers for some platforms.