Frequencies for first 10,000 rows of comstat8 variable in nhamcsopd2004 dataset :

composition status |
          code for |
     medication #8 |      Freq.     Percent        Cum.
-------------------+-----------------------------------
single entity drug |        501        5.01        5.01
  combination drug |         52        0.52        5.53
      undetermined |         14        0.14        5.67
                 . |      9,433       94.33      100.00
-------------------+-----------------------------------
             Total |     10,000      100.00

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