Frequencies for first 10,000 rows of ocntyfips variable in natlterr2011 dataset :

 Occurrence |
FIPS County |
        U;R |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      2,289       22.89       22.89
         10 |      3,297       32.97       55.86
         21 |        480        4.80       60.66
         25 |        307        3.07       63.73
         31 |        106        1.06       64.79
         97 |        281        2.81       67.60
        113 |        575        5.75       73.35
        127 |      1,286       12.86       86.21
        999 |      1,379       13.79      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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