Frequencies for first 10,000 rows of ocntyfips variable in linkpe2009psden dataset :

 Occurrence |
FIPS County |
        U;R |      Freq.     Percent        Cum.
------------+-----------------------------------
        127 |      1,832       18.32       18.32
        999 |      8,168       81.68      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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