Frequencies for first 10,000 rows of comstat4 variable in nhamcsed2005 dataset :

composition status |
              code |      Freq.     Percent        Cum.
-------------------+-----------------------------------
single entity drug |      1,185       11.85       11.85
  combination drug |        221        2.21       14.06
      undetermined |         35        0.35       14.41
                 . |      8,559       85.59      100.00
-------------------+-----------------------------------
             Total |     10,000      100.00

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