It wouldn't really be that tough to check out actually.
As far as overall usage, numbers are down since it is still the summer. My off the cuff interpretation is it looks like the Big 4 use dropped by 1-2% for each plane. The Spit V is taking up much of the slack, as is the 190d9 and 109g10. I suspect the Spit V is the plane of choice when the Spit IX and Niki are disabled, and the D-9 is the plane of choice for when the La7 gets disabled.