Frequencies for first 10,000 rows of pgm_prtcptn_cd variable in pos2007 dataset :

    program |
participati |
         on |      Freq.     Percent        Cum.
------------+-----------------------------------
            |      4,338       43.38       43.38
          1 |        556        5.56       48.94
          2 |        868        8.68       57.62
          3 |      4,238       42.38      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 17 May 2017