Frequencies for first 10,000 rows of comstat2 variable in nhamcsed2014 dataset :

Composition status |
          code for |
     medication #2 |      Freq.     Percent        Cum.
-------------------+-----------------------------------
Single entity drug |      4,674       46.74       46.74
  Combination drug |        706        7.06       53.80
      Undetermined |         53        0.53       54.33
                 . |      4,567       45.67      100.00
-------------------+-----------------------------------
             Total |     10,000      100.00

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