Explain why the data reported here might be a poor indicator of the differences in economic welfare among Canada, the United Kingdom, and the United States, but nevertheless provide the correct ranking of the countries.

The International Monetary Fund reported the following data on gross domestic product per capita, measured in U.S. dollars at market exchange rates in 2019: Canada $46,400, China $10,243, United Kingdom $42,417, and United States $65,254.