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

  DRUG TEST |
     TYPE-2 |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      9,508       95.08       95.08
          1 |        312        3.12       98.20
          2 |         32        0.32       98.52
          3 |         31        0.31       98.83
          8 |         10        0.10       98.93
          9 |        107        1.07      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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