Frequencies for first 10,000 rows of cntocpop variable in natl1998 dataset :

 Population |
    Size of |
  County of |
 Occurrence |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |      2,298       22.98       22.98
          2 |      1,260       12.60       35.58
          3 |      2,901       29.01       64.59
          9 |      3,541       35.41      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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