Frequencies for first 10,000 rows of prov0070 variable in pos1991 dataset :

       capd |
certificati |
         on |      Freq.     Percent        Cum.
------------+-----------------------------------
            |      9,987       99.87       99.87
          A |         10        0.10       99.97
          B |          3        0.03      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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