Frequencies for first 10,000 rows of prov2420 variable in pos1998 dataset :

       srv: |
psychologic |
         al |      Freq.     Percent        Cum.
------------+-----------------------------------
            |      9,942       99.42       99.42
          0 |         16        0.16       99.58
          1 |         11        0.11       99.69
          2 |         14        0.14       99.83
          3 |         17        0.17      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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