Frequencies for first 10,000 rows of citrspop variable in natl1980 dataset :

 Population |
     size - |
   place of |
  residence |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |          3        0.03        0.03
          2 |        844        8.44        8.47
          3 |      1,178       11.78       20.25
          9 |      7,974       79.74       99.99
          Z |          1        0.01      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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