Frequencies for first 10,000 rows of hincomer variable in nhamcsopd2007 dataset :

  median household income in |
               patient's zip |      Freq.     Percent        Cum.
-----------------------------+-----------------------------------
                missing data |        366        3.66        3.66
  quartile 1 (below $32,793) |      3,497       34.97       38.63
quartile 2 ($32,794-$40,626) |      2,124       21.24       59.87
quartile 3 ($40,627-$52,387) |      1,953       19.53       79.40
quartile 4 ($52,388 or more) |      2,060       20.60      100.00
-----------------------------+-----------------------------------
                       Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 28 Mar 2016