There are two similar question on the site:
The first is asking where the users of Bitcoin are located. The second is asking about percentage distributions among those users. Interesting data.
What I want to know is the geographic distribution of the bitcoins themselves. For example, what percentage of the bitcoin supply is held by North Americans (or North American companies)?
This tool supposedly gets data from "Mt. Gox, Bitstamp and BTC China to show you which countries and which currencies are moving in and out of bitcoin in real time." I'm assuming it's just Mt. Gox and Bitstamp now and possibly others.
As of September 2019, the exchanges from which the data seem to come are listed under "exchange" in the bottom left of the tool. Perhaps take it with a grain of salt, as there's some obvious errors, such as gdax still being listed along with coinbase pro. Gdax was rebranded as coinbase pro about two years ago. The listed exchanges are: