In an interview during the 90's, William Shatner told of a story of him being recognized in mid-perfomance by a sword dancer in a small Iranian village. The man stopped dead in his tracks and looked straight at him uttering with utter amazement; "Captain Kirk?!?" That should give us perspective as to how deep and far Star Trek reached people for the last 51 years.
Source: https://www.quora.com/What-is-the-approximate-number-of-Star-Trek-fans-worldwide