I’m not in any way involved with secondary education and don’t claim to be an expert, but it seems to me that the problem is more with political boards than the teachers.
Perhaps so ... I’d be interested to see the data. I’d expect it to be quite a bit worse in grade and high school than in college and university.
The other issue is how scared the teachers are to actually teach what they believe. That is, it does little good for a class to have smart teachers if the teachers feels they are not free to discuss evolution in the classroom. Again, I don’t think that’s going to be the case at colleges and universities, but I have heard anecdotal stories from public grade and high schools. To ferret that out they’d need to ask some additional questions.
It occurs to me that there’s yet another problem, which is that it might be creationist teachers would be less likely to respond to a survey like this than biology teachers who believed in evolution. If so, there would be an additional statistical bias in the data.