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

  DRUG TEST |
     TYPE-1 |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      6,974       69.74       69.74
          1 |      1,301       13.01       82.75
          2 |        156        1.56       84.31
          3 |        105        1.05       85.36
          7 |         92        0.92       86.28
          8 |         18        0.18       86.46
          9 |      1,354       13.54      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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