Were non-Force believers like Han Solo common?

During the PT era and for thousands of years before it, the Jedi were famed as Force-users. Evidence of their command of the Force was common. Even ordinary denizens of the GFFA might have seen Jedi Force-feats at work. As such, probably everybody knew of the existence of the Force. A mere twenty years later, however, you had people like Han Solo...who did not believe the Force existed. How common was this view by the time of the OT? Could a belief system that had endured for thousands of years truly be forgotten in a mere twenty years, even if few of its practitioners are known to still be alive?

 

Probably a lot of them out there. I mean, there's scientific probability for the illusion of jedi superiority.