Frequencies for first 10,000 rows of comstat1 variable in nhamcsed2014 dataset :

Composition status |
          code for |
     medication #1 |      Freq.     Percent        Cum.
-------------------+-----------------------------------
Single entity drug |      6,726       67.26       67.26
  Combination drug |      1,073       10.73       77.99
      Undetermined |         92        0.92       78.91
                 . |      2,109       21.09      100.00
-------------------+-----------------------------------
             Total |     10,000      100.00

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