You could easily calculate such a stat from here. Microsoft Apple and Google are all in the top 5, with IBM and Oracle being the other two. Adobe used to be on top but with the death of flash they have been slipping. I checked out the breakdown of memory corruption/overflow bugs and its well over 50% of CVEs for MS and Apple. Google is much better with less then a quarter of their CVEs being memory related.
You're not talking about the same thing: the ggp asked how many CVE were dedicated to Apple, Microsoft or Google products (a question that doesn't make much sense here, but the gp still went on the calculation). You are talking about which proportions of thoses big corps CVE are memory-related (which is the right question to ask in this context, but not the one asked…).
