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

  DRUG TEST |
     TYPE-3 |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      9,751       97.51       97.51
          1 |        114        1.14       98.65
          2 |          6        0.06       98.71
          3 |         19        0.19       98.90
          8 |          3        0.03       98.93
          9 |        107        1.07      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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