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

 Population |
    Size of |
  County of |
  Residence |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |          1        0.01        0.01
          1 |      1,586       15.86       15.87
          2 |      1,011       10.11       25.98
          3 |      2,030       20.30       46.28
          9 |      5,371       53.71       99.99
          Z |          1        0.01      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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