Frequencies for first 10,000 rows of cntocpop variable in natl1993 dataset :

 Population |
    Size of |
  County of |
 Occurrence |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |      2,311       23.11       23.11
          2 |      1,109       11.09       34.20
          3 |      2,745       27.45       61.65
          9 |      3,835       38.35      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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