Frequencies for first 10,000 rows of drugtst3 variable in person dataset :

  DRUG TEST |
     TYPE-3 |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      9,847       98.47       98.47
          1 |         83        0.83       99.30
          2 |         16        0.16       99.46
          3 |         16        0.16       99.62
          7 |          1        0.01       99.63
          8 |          8        0.08       99.71
          9 |         29        0.29      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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