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

  DRUG TEST |
       TYPE |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      7,611       76.11       76.11
          1 |      1,489       14.89       91.00
          2 |        150        1.50       92.50
          7 |         15        0.15       92.65
          8 |         26        0.26       92.91
          9 |        709        7.09      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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