Frequencies for first 10,000 rows of hincomer variable in nhamcsed2009 dataset :

     median |
  household |
  income in |
  patient's |
   zip code |      Freq.     Percent        Cum.
------------+-----------------------------------
         -9 |        709        7.09        7.09
          1 |      2,860       28.60       35.69
          2 |      2,290       22.90       58.59
          3 |      1,945       19.45       78.04
          4 |      2,196       21.96      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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