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

  DRUG TEST |
     TYPE-3 |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      9,874       98.74       98.74
          1 |         60        0.60       99.34
          2 |         25        0.25       99.59
          3 |         27        0.27       99.86
          7 |          2        0.02       99.88
          8 |         12        0.12      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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