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

  DRUG TEST |
     TYPE-3 |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      9,733       97.33       97.33
          1 |         27        0.27       97.60
          2 |         48        0.48       98.08
          3 |          5        0.05       98.13
          7 |         13        0.13       98.26
          9 |        174        1.74      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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