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

  DRUG TEST |
     TYPE-2 |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      9,487       94.87       94.87
          1 |        254        2.54       97.41
          2 |         32        0.32       97.73
          3 |         36        0.36       98.09
          7 |          7        0.07       98.16
          8 |          5        0.05       98.21
          9 |        179        1.79      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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