Frequencies for first 10,000 rows of citrspop variable in natl1987 dataset :

 Population |
     size - |
   place of |
  residence |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |          2        0.02        0.02
          2 |        535        5.35        5.37
          3 |      1,686       16.86       22.23
          9 |      7,776       77.76       99.99
          Z |          1        0.01      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 3 Jan 2016