Frequencies for first 10,000 rows of comstat3 variable in nhamcsed2008 dataset :

          for rx3, |
composition status |
              code |      Freq.     Percent        Cum.
-------------------+-----------------------------------
single entity drug |      2,609       26.09       26.09
  combination drug |        500        5.00       31.09
                 . |      6,891       68.91      100.00
-------------------+-----------------------------------
             Total |     10,000      100.00

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