Frequencies for first 10,000 rows of comstat5 variable in nhamcsopd2010 dataset :

composition status |
              code |      Freq.     Percent        Cum.
-------------------+-----------------------------------
single entity drug |      2,046       20.46       20.46
  combination drug |        187        1.87       22.33
      undetermined |         31        0.31       22.64
                 . |      7,736       77.36      100.00
-------------------+-----------------------------------
             Total |     10,000      100.00

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