Frequencies for first 10,000 rows of comstat7 variable in nhamcsed2013 dataset :

Composition status |
          code for |
     medication #7 |      Freq.     Percent        Cum.
-------------------+-----------------------------------
Single entity drug |        386        3.86        3.86
  Combination drug |         45        0.45        4.31
      Undetermined |          7        0.07        4.38
                 . |      9,562       95.62      100.00
-------------------+-----------------------------------
             Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 7 Nov 2016