Frequencies for first 10,000 rows of comstat5 variable in nhamcsed2010 dataset :

Composition status |
              code |      Freq.     Percent        Cum.
-------------------+-----------------------------------
single entity drug |        908        9.08        9.08
  combination drug |        154        1.54       10.62
      undetermined |         10        0.10       10.72
                 . |      8,928       89.28      100.00
-------------------+-----------------------------------
             Total |     10,000      100.00

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