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

  DRUG TEST |
     TYPE-1 |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      7,309       73.09       73.09
          1 |      1,711       17.11       90.20
          2 |        101        1.01       91.21
          3 |         81        0.81       92.02
          7 |         31        0.31       92.33
          8 |         25        0.25       92.58
          9 |        742        7.42      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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