Frequencies for first 10,000 rows of comstat7 variable in nhamcsed2004 dataset :

composition status |
          code for |
     medication #7 |      Freq.     Percent        Cum.
-------------------+-----------------------------------
single entity drug |        444        4.44        4.44
  combination drug |         52        0.52        4.96
      undetermined |         14        0.14        5.10
                 . |      9,490       94.90      100.00
-------------------+-----------------------------------
             Total |     10,000      100.00

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