Frequencies for first 10,000 rows of comstat7 variable in nhamcsed2010 dataset :

Composition status |
              code |      Freq.     Percent        Cum.
-------------------+-----------------------------------
single entity drug |        286        2.86        2.86
  combination drug |         28        0.28        3.14
      undetermined |          5        0.05        3.19
                 . |      9,681       96.81      100.00
-------------------+-----------------------------------
             Total |     10,000      100.00

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