Frequencies for first 10,000 rows of prov2420 variable in pos1996 dataset :

       srv: |
psychologic |
         al |      Freq.     Percent        Cum.
------------+-----------------------------------
            |      9,943       99.43       99.43
          0 |         15        0.15       99.58
          1 |         15        0.15       99.73
          2 |         11        0.11       99.84
          3 |         16        0.16      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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