Frequencies for first 10,000 rows of comstat3 variable in nhamcsed2004 dataset :

composition status |
          code for |
     medication #3 |      Freq.     Percent        Cum.
-------------------+-----------------------------------
single entity drug |      2,506       25.06       25.06
  combination drug |        439        4.39       29.45
      undetermined |         76        0.76       30.21
                 . |      6,979       69.79      100.00
-------------------+-----------------------------------
             Total |     10,000      100.00

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