Frequencies for first 10,000 rows of comstat3 variable in nhamcsopd2008 dataset :

          for rx3, |
composition status |
              code |      Freq.     Percent        Cum.
-------------------+-----------------------------------
single entity drug |      3,193       31.93       31.93
  combination drug |        366        3.66       35.59
      undetermined |          2        0.02       35.61
                 . |      6,439       64.39      100.00
-------------------+-----------------------------------
             Total |     10,000      100.00

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