Frequencies for first 10,000 rows of agi_class variable in zipcode2008 dataset :

  agi_class |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |      1,497       14.97       14.97
          2 |      1,497       14.97       29.94
          3 |      1,497       14.97       44.91
          4 |      1,496       14.96       59.87
          5 |      1,493       14.93       74.80
          6 |      1,463       14.63       89.43
          7 |      1,057       10.57      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 20 Jun 2017