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

       DRUG |
INVOLVEMENT |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      1,893       18.93       18.93
          1 |        213        2.13       21.06
          8 |      6,219       62.19       83.25
          9 |      1,675       16.75      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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