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

  DRUG TEST |
     TYPE-2 |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      9,795       97.95       97.95
          1 |         79        0.79       98.74
          2 |         57        0.57       99.31
          3 |          9        0.09       99.40
          7 |          7        0.07       99.47
          9 |         53        0.53      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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