Frequencies for first 10,000 rows of comstat6 variable in nhamcsopd2011 dataset :

Composition status |
          code for |
     Medication #6 |      Freq.     Percent        Cum.
-------------------+-----------------------------------
Single entity drug |      1,489       14.89       14.89
  Combination drug |        106        1.06       15.95
      Undetermined |         11        0.11       16.06
                 . |      8,394       83.94      100.00
-------------------+-----------------------------------
             Total |     10,000      100.00

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