Frequencies for first 10,000 rows of comstat7 variable in nhamcsopd2011 dataset :

Composition status |
          code for |
     Medication #7 |      Freq.     Percent        Cum.
-------------------+-----------------------------------
Single entity drug |      1,144       11.44       11.44
  Combination drug |         87        0.87       12.31
      Undetermined |         19        0.19       12.50
                 . |      8,750       87.50      100.00
-------------------+-----------------------------------
             Total |     10,000      100.00

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