Frequencies for first 10,000 rows of ocntyfips variable in natl2003 dataset :

 Occurrence |
FIPS County |
        U;R |      Freq.     Percent        Cum.
------------+-----------------------------------
         20 |      5,428       54.28       54.28
         73 |          2        0.02       54.30
        101 |          4        0.04       54.34
        125 |          1        0.01       54.35
        999 |      4,565       45.65      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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