Frequencies for first 10,000 rows of comstat6 variable in nhamcsopd2009 dataset :

          for rx6, |
composition status |
              code |      Freq.     Percent        Cum.
-------------------+-----------------------------------
single entity drug |      1,527       15.27       15.27
  combination drug |        133        1.33       16.60
      undetermined |         17        0.17       16.77
                 . |      8,323       83.23      100.00
-------------------+-----------------------------------
             Total |     10,000      100.00

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