And non-voters and independents are in between, and closer to Republicans on that "issue."
Also, more worryingly, 31% of Republicans say they are "not sure" if the crazy theory is true, meaning only about one in four Republicans is grounded in reality. And this isn't the only issue like that.
That's the problem with American politics in a nutshell. The base of one of our two parties is not just unaware of basic facts (that actually applies to both sides), but is living in a complete fantasy world and has mentally cut itself off from any source of true information. On top of that, the legitimate media is committed by ideology and by its business model to pretending that both sides are the same. So one big chunk of the population is getting lied to and taught to hate everyone else in the country, and another big chunk is hearing that the truth is halfway between the truth and a bunch of wild fantasies. It's a miracle that we are able to maintain a modern society in the face of this.