Frequencies for first 10,000 rows of comstat1 variable in nhamcsed2004 dataset :

composition status |
          code for |
     medication #1 |      Freq.     Percent        Cum.
-------------------+-----------------------------------
single entity drug |      6,174       61.74       61.74
  combination drug |      1,352       13.52       75.26
      undetermined |        128        1.28       76.54
                 . |      2,346       23.46      100.00
-------------------+-----------------------------------
             Total |     10,000      100.00

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