Census money income statistics

This link from http://www.census.gov/compendia/statab/cats/income_expenditures_poverty_wealth.html is a much better presenter of income sensus. Even allows to copy and past:

YEAR	$15K	25K	$35K	$50K	$75K	over
1967	10.7%	11.3%	14.0%	22.1%	25.6%	16.3%
1970	9.2	10.6	12.0	20.8	26.2	21.1
1980	8.8	10.5	11.4	17.1	24.8	27.4
1990	8.6	9.4	10.2	15.6	22.4	33.8
2008	8.1	9.0	9.7	13.6	19.4	40.3

I was going to use this table as evidence that lower tax rates prompt more middle people to higher brackets, but because I don't have the data in 50s, it is not conclusive.