Frequencies for first 10,000 rows of participate variable in pos1988 dataset :

Participati |
         ng |
Non-Partici |
     pating |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      1,177       11.77       11.77
          1 |      5,919       59.19       70.96
          2 |      1,647       16.47       87.43
          3 |      1,254       12.54       99.97
          . |          3        0.03      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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