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

       DRUG |
DETERMAINAT |
        ION |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |        214        2.14        2.14
          2 |         33        0.33        2.47
          3 |         25        0.25        2.72
          7 |        107        1.07        3.79
          8 |      9,621       96.21      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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