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

       DRUG |
DETERMAINAT |
        ION |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |         25        0.25        0.25
          2 |         14        0.14        0.39
          3 |          1        0.01        0.40
          7 |         57        0.57        0.97
          8 |      9,903       99.03      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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