Frequencies for first 10,000 rows of comstat3 variable in nhamcsopd2011 dataset :

Composition status |
          code for |
     Medication #3 |      Freq.     Percent        Cum.
-------------------+-----------------------------------
Single entity drug |      3,297       32.97       32.97
  Combination drug |        325        3.25       36.22
      Undetermined |         34        0.34       36.56
                 . |      6,344       63.44      100.00
-------------------+-----------------------------------
             Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 28 Mar 2016