Frequencies for first 10,000 rows of comstat7 variable in nhamcsopd2008 dataset :

          for rx7, |
composition status |
              code |      Freq.     Percent        Cum.
-------------------+-----------------------------------
single entity drug |      1,124       11.24       11.24
  combination drug |         95        0.95       12.19
      undetermined |          2        0.02       12.21
                 . |      8,779       87.79      100.00
-------------------+-----------------------------------
             Total |     10,000      100.00

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