I thought the mainstream creationist position was somewhere between Old Earth and intelligent design. When was the last time this was polled?
To the contrary. Having grown up in a majority evangelical state - almost all of whom are YECers - there is also some debate about the existence of dinosaurs.
https://news.gallup.com/poll/261680/americans-believe-creationism.aspx (40% agreeing is also among the smallest percentage in the last 50 years)
Polling on this issue is generally terrible and seems designed to find a high percentage of people rejecting evolution in some form or other. The correct questions to ask are:
1) Based on what you have heard, do you think that the theory of evolution is mostly true or mostly false?
2) Do you think that the theory of evolution should be taught in school?
When asked this way, IIRC around 2/3 of the population believes in evolution.