Frequencies for first 10,000 rows of comstat7 variable in nhamcsopd2003 dataset :

composition status |
          code for |
     medication #7 |      Freq.     Percent        Cum.
-------------------+-----------------------------------
single entity drug |        638        6.38        6.38
  combination drug |         61        0.61        6.99
      undetermined |         23        0.23        7.22
                 . |      9,278       92.78      100.00
-------------------+-----------------------------------
             Total |     10,000      100.00

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