Frequencies for first 10,000 rows of comstat4 variable in nhamcsed2015 dataset 

Composition status |
          code for |
     medication #4 |      Freq.     Percent        Cum.
-------------------+-----------------------------------
Single entity drug |      2,132       21.32       21.32
  Combination drug |        268        2.68       24.00
      Undetermined |         28        0.28       24.28
                 . |      7,572       75.72      100.00
-------------------+-----------------------------------
             Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 20 Nov 2017