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

   Revision |
        U;R |      Freq.     Percent        Cum.
------------+-----------------------------------
          A |      6,578       65.78       65.78
          S |      3,422       34.22      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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