Frequencies for first 10,000 rows of drug_det variable in person dataset :

       DRUG |
DETERMAINAT |
        ION |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |         22        0.22        0.22
          2 |         18        0.18        0.40
          3 |          4        0.04        0.44
          7 |         81        0.81        1.25
          8 |      9,875       98.75      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 18 Apr 2016