Frequencies for first 10,000 rows of comstat20 variable in nhamcsed2014 dataset :

Composition status |
          code for |
    medication #20 |      Freq.     Percent        Cum.
-------------------+-----------------------------------
Single entity drug |         18        0.18        0.18
  Combination drug |          5        0.05        0.23
                 . |      9,977       99.77      100.00
-------------------+-----------------------------------
             Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 11 Apr 2017