Frequencies for first 10,000 rows of comstat3 variable in nhamcsed2005 dataset :

composition status |
              code |      Freq.     Percent        Cum.
-------------------+-----------------------------------
single entity drug |      2,153       21.53       21.53
  combination drug |        454        4.54       26.07
      undetermined |         76        0.76       26.83
                 . |      7,317       73.17      100.00
-------------------+-----------------------------------
             Total |     10,000      100.00

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