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

       DRUG |
INVOLVEMENT |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      1,868       18.68       18.68
          1 |        162        1.62       20.30
          8 |      6,517       65.17       85.47
          9 |      1,453       14.53      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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