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

  DRUG TEST |
     TYPE-3 |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      9,919       99.19       99.19
          1 |         32        0.32       99.51
          2 |         12        0.12       99.63
          3 |          2        0.02       99.65
          8 |          1        0.01       99.66
          9 |         34        0.34      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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