I don't know how many I have, but I have A LOT!!! I also have a thing that my bra and panty HAVE to match (not sure if others feel that way or not), so I will only purchase a bra if there are matching panties.
It is definitely time for me to go through my drawer and get rid of the older ones. I have a lot in there that don't fit properly. I had a bra fitting a couple of years ago and found that I was wearing the wrong size. Thought I was a 36C but turned out I was a 34DD. I think I still have a bunch of the wrong size at the bottom of my drawer.