Frequencies for first 10,000 rows of comstat5 variable in nhamcsed2008 dataset :

          for rx5, |
composition status |
              code |      Freq.     Percent        Cum.
-------------------+-----------------------------------
single entity drug |        734        7.34        7.34
  combination drug |        131        1.31        8.65
      undetermined |          1        0.01        8.66
                 . |      9,134       91.34      100.00
-------------------+-----------------------------------
             Total |     10,000      100.00

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