Frequencies for first 10,000 rows of prov2420 variable in pos1993 dataset :

       srv: |
psychologic |
         al |      Freq.     Percent        Cum.
------------+-----------------------------------
            |      9,960       99.60       99.60
          0 |          9        0.09       99.69
          1 |          7        0.07       99.76
          2 |         11        0.11       99.87
          3 |         13        0.13      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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