Frequencies for first 10,000 rows of prov0090 variable in pos1995 dataset :

       ccpd |
certificati |
         on |      Freq.     Percent        Cum.
------------+-----------------------------------
            |      9,994       99.94       99.94
          A |          6        0.06      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 26 Jan 2016