Considering the fact that there are 50 different states (countries) that operate their own DMVs using different laws, I doubt you will find the information you desire, as the DMVs do not differentiate between Class A, Class B, or Class C. Therefore, the closest information I can offer you is this little piece from the Recreational Vehicle Industry Association:
New RVIA Research Shows Record Level of RV Ownership. If you dig further into the RVIA web site, you will find the
Historical Glance: RV Wholesale Shipments Deliveries Annually from Manufacturers to Dealers 1978-2012. If you dig far enough, you might find the info you want.
