Frequencies for first 10,000 rows of comstat7 variable in nhamcsed2005 dataset :

composition status |
              code |      Freq.     Percent        Cum.
-------------------+-----------------------------------
single entity drug |        170        1.70        1.70
  combination drug |         22        0.22        1.92
      undetermined |          3        0.03        1.95
                 . |      9,805       98.05      100.00
-------------------+-----------------------------------
             Total |     10,000      100.00

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