The World Top Incomes Database, host by PSE-Paris School of Economics, is a study of the distribution of top incomes, aggregated from countries tax data.

Data including top income population share, income composition, capital gains, earnings and wealth distribution, averages for a decent coverage of the globe, as well as data going back to the early 1900s are available on the site.

It’s clearly a work in progress, but it’s also a very ambitious project.