Frequencies for first 10,000 rows of comstat6 variable in nhamcsopd2007 dataset :

          for rx6, |
composition status |
              code |      Freq.     Percent        Cum.
-------------------+-----------------------------------
single entity drug |      1,328       13.28       13.28
  combination drug |        147        1.47       14.75
      undetermined |          4        0.04       14.79
                 . |      8,521       85.21      100.00
-------------------+-----------------------------------
             Total |     10,000      100.00

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