On the White House website, as of 7PM Eastern on April 10, you can find the following graph
Now if you read to the bottom, you'll see the source as "CBO." I found this pretty interesting because, to my knowledge, the CBO has never published effective tax rates back to 1960. I know because I've spent a lot of time looking for them.
They have published effective tax rates back to 1979 and you can find those here. Let's do a quick comparison. The WH chart shows the effective tax rates of the top 0.1% as below those of the top 1% from 2003 on and says the source is the CBO. Meanwhile the CBO data (which only goes through 2005) shows no such thing. The WH chart also appears to show (based on interpreting the axes) far higher tax rates than were actually in place according to the CBO report in 1980. But since they haven't published the data or linked to the CBO, it's a bit hard to know.
But it's this chart that allows the WH to argue that tax rates have declined by more than 50 percent for "the wealthy." Meanwhile the CBO data for the top 0.01% shows a decline of about 30 percent from 1979 to 2005, pretty much the same decline in percentage terms as most income groups although less than those in the bottom quintile.
So I'm left with 2 questions: Did the WH misquote the CBO? If they did, where did the data come from? If they didn't, can they show us the CBO data?
Update: The White House shows in a different report the same data but in this report, they clearly source the data as not coming from the CBO and not even being actual data but rather data created by the CEA. The specific quote is: "Average Federal tax rates for a sample of 2005 taxpayers after adjusting for growth in the national wage index" and the source is basically CEA analysis. CEA/CBO what's the difference?