Frequencies for first 10,000 rows of rcnty_pop variable in natl2004 dataset :

 Population |
         of |
  Residence |
 County U;R |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |          1        0.01        0.01
          1 |          3        0.03        0.04
          2 |      4,260       42.60       42.64
          3 |          6        0.06       42.70
          9 |      5,727       57.27       99.97
          Z |          3        0.03      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 21 Jan 2016