[fuser]

For all the statistics used in the famous book of Thomas Piketty's famous book "Capital in 21st Century" :

http://piketty.pse.ens.fr/en/capital21c2

And another great site for statistics presented in the books "Top Incomes : a Global Perspective and Top Incomes over the XXth Century " analysing long term evolution of top incomes in 22 (and counting) countries.

The World Top Income Database