Frequencies for first 10,000 rows of citrspop variable in natl1997 dataset :

 Population |
     size - |
   place of |
  residence |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |          2        0.02        0.02
          2 |        706        7.06        7.08
          3 |      1,474       14.74       21.82
          9 |      7,815       78.15       99.97
          Z |          3        0.03      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 22 Dec 2015