Frequencies for first 10,000 rows of comstat1 variable in nhamcsopd2003 dataset :

composition status |
          code for |
     medication #1 |      Freq.     Percent        Cum.
-------------------+-----------------------------------
single entity drug |      5,032       50.32       50.32
  combination drug |        907        9.07       59.39
      undetermined |        197        1.97       61.36
                 . |      3,864       38.64      100.00
-------------------+-----------------------------------
             Total |     10,000      100.00

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