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

 Population |
    Size of |
    City of |
  Residence |      Freq.     Percent        Cum.
------------+-----------------------------------
          2 |        750        7.50        7.50
          3 |      1,380       13.80       21.30
          9 |      7,869       78.69       99.99
          Z |          1        0.01      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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