Frequencies for first 10,000 rows of comstat5 variable in nhamcsed2005 dataset :

composition status |
              code |      Freq.     Percent        Cum.
-------------------+-----------------------------------
single entity drug |        602        6.02        6.02
  combination drug |         89        0.89        6.91
      undetermined |         16        0.16        7.07
                 . |      9,293       92.93      100.00
-------------------+-----------------------------------
             Total |     10,000      100.00

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