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

  DRUG TEST |
     TYPE-3 |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      9,933       99.33       99.33
          1 |         22        0.22       99.55
          2 |         19        0.19       99.74
          3 |         12        0.12       99.86
          7 |          2        0.02       99.88
          8 |          1        0.01       99.89
          9 |         11        0.11      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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