Frequencies for first 10,000 rows of cntocpop variable in natl2000 dataset :

 Population |
    Size of |
  County of |
 Occurrence |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |      2,341       23.41       23.41
          2 |      1,215       12.15       35.56
          3 |      2,914       29.14       64.70
          9 |      3,530       35.30      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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