Frequencies for first 10,000 rows of comstat6 variable in nhamcsed2010 dataset :

Composition status |
              code |      Freq.     Percent        Cum.
-------------------+-----------------------------------
single entity drug |        485        4.85        4.85
  combination drug |         86        0.86        5.71
      undetermined |          3        0.03        5.74
                 . |      9,426       94.26      100.00
-------------------+-----------------------------------
             Total |     10,000      100.00

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