Frequencies for first 10,000 rows of drugtst2 variable in person dataset :

  DRUG TEST |
     TYPE-2 |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      9,640       96.40       96.40
          1 |         66        0.66       97.06
          2 |         96        0.96       98.02
          3 |          9        0.09       98.11
          7 |         15        0.15       98.26
          9 |        174        1.74      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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