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

       DRUG |
INVOLVEMENT |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      2,301       23.01       23.01
          1 |        244        2.44       25.45
          8 |      5,770       57.70       83.15
          9 |      1,685       16.85      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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