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

  DRUG TEST |
     TYPE-1 |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      7,676       76.76       76.76
          1 |      1,852       18.52       95.28
          2 |        126        1.26       96.54
          3 |         85        0.85       97.39
          7 |         54        0.54       97.93
          8 |         26        0.26       98.19
          9 |        181        1.81      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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