The top marginal rates don't reflect what is actually paid in taxes. The tax laws are complex, very complex for high income people. Although the top marginal rates for individuals has come down dramatically from the highs of decades ago in the USA, the actual tax paid as a percentage of total income has gone up in the US for the top 10%.

The USA has a very progressive tax system. The top 20% of earners in the USA make 51% of total US income(2014) and pay 84% of total US income tax.

This data is pretty easy to find: OECD publications, see [1], WSJ see [2]

[1] http://darp.lse.ac.uk/resources/books/GrowingUnequal_OECD.pd...

[2] http://www.wsj.com/articles/top-20-of-earners-pay-84-of-inco...