https://www.scientificamerican.com/article/do-you-have-what-it-takes-to-be-an-astronaut/

As of December 4, 2019, 565 people from 41 countries have gone into space. That’s it. 565 out of more than 7 billion of us currently on this planet. And that's using the definition of space travel to include any flight over 62 miles or about 100 kilometers.

Many of these space travelers are, of course, NASA astronauts. That means they went through a rigorous application and training process. So, what exactly does it take to be an astronaut?