I don't know how much of an effect this has on the data(is this indigenous species only), but there is something that might be slightly misleading about the Texas data. Due to the proliferation of non-indigenous species hunting in Texas, you can find species that, while on the world endangered list, are actually thriving there due to farming(for hunting). One example that I know of firsthand is Oryx dammah. While this species is IUCN EW, they are being bred very successfully in Texas. So while I'm sure it counts as an endangered species in Texas, it isn't because they are being forced into extinction there. I'm guessing they are not unique in that scenario. Anyway, just thought I'd toss that in for discussion.