There’s also this from the JEC:

Congressional Budget Office (CBO) data show that the total effective federal tax rate of the middle fifth of households declined after 2001 to its lowest levels since at least 1979, Congressman Jim Saxton, ranking member of the Joint Economic Committee, said today. Under the 2001 and 2003 tax relief legislation, the income tax as a share of income for the middle fifth also has fallen to its lowest levels in decades.