Frequencies for first 10,000 rows of drugtst1 variable in person dataset :

  DRUG TEST |
     TYPE-1 |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      7,228       72.28       72.28
          1 |      2,445       24.45       96.73
          2 |         27        0.27       97.00
          3 |        105        1.05       98.05
          7 |         18        0.18       98.23
          8 |         33        0.33       98.56
          9 |        144        1.44      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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