It was a tidbit that I ran across in https://www.youtube.com/watch?v=A9UmdY0E8hU which had some other interesting data points as well. Such as the fact that when you look at rich people per capita, it seems that social democracies like Canada, and Scandinavia create rich people more easily than the USA does.

For example if you look for people worth $30million+ per million people, Canada has 186 while the USA has 126. That's about a third more per capita.

And watching the video, you find that 42% of the children of the bottom 20% in the USA wind up in the bottom 20%. Very little of Canada does anything like that poorly.