Found this on CadDigest, it relates to the original purchasing of Revit by AutoDesk in 2002, I found the Graphisoft quote amusing:
“If the government approves, Autodesk hopes to complete its US$133 million-purchase of Revit Technologies by the end of July. Government approval is not a given, however, because the concentration of ownership. How do competitors Graphisoft and Nemetschek feel about it? Graphisoft likes the purchase because it eliminates a competitor; they think Revit will go the way of SoftDesk”
You can find the full article HERE
I will be investigating to try and find out just how many Revit users there are now.