Frequencies for first 10,000 rows of comstat3 variable in nhamcsed2010 dataset :

Composition status |
              code |      Freq.     Percent        Cum.
-------------------+-----------------------------------
single entity drug |      2,845       28.45       28.45
  combination drug |        507        5.07       33.52
      undetermined |         27        0.27       33.79
                 . |      6,621       66.21      100.00
-------------------+-----------------------------------
             Total |     10,000      100.00

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