There are alot of 750's here. As they were made from '85 to '06 , even if not a popular model here, they sold fairly well.
I have no idea of exact figures, but would say they are not hard to find ....in running condition..
. We have 4000 members here, so that's at least 4000 right?
The numbers however will begin to go down, as older models die off or get replaced...this happens to all discontinued bikes....the thing the 750 has going for it is the many production years.
Some models only go a few years before they are dropped, so finding those tends to be harder.