Frequencies for first 10,000 rows of cntocpop variable in natl2001 dataset :

 Population |
    Size of |
  County of |
 Occurrence |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |      2,489       24.89       24.89
          2 |      1,223       12.23       37.12
          3 |      2,775       27.75       64.87
          9 |      3,513       35.13      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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