I guess we'll never know!
Following on from the post below about whether wine critics should provide details of all wines tasted and not just those scoring above a particular point range or quality level, I asked a question on the Mark Squires forums of eRobertParker.com about the availability of information on the total number of wines tasted. Mr Parker was kind enough to provide an answer through his ERPSupport people. Mike, we checked with Mr. Parker who says: "No totally accurate record exists as we do not always record all of the wines rated below 84. In general, what is published represents approximately 25-35% of the total number of wines tasted."
So now you know!