No such numbers are available.
That said, I tend to think that we sold more of the Planar Driver speakers overall, but again I don't know how many years Brian offered the pre-planar models and how that production added up.
I do know that I started with Brian around 2002 or 2003 and he often told me that I doubled or tripled his overall sales.
I might suggest that the reason you see more of the older speakers, is that the owners of the Planar MR speakers want to keep them.