Frequencies for first 10,000 rows of comstat5 variable in nhamcsopd2006 dataset :

          for rx5, |
composition status |
              code |      Freq.     Percent        Cum.
-------------------+-----------------------------------
Single entity drug |      1,310       13.10       13.10
  Combination drug |        132        1.32       14.42
                 . |      8,558       85.58      100.00
-------------------+-----------------------------------
             Total |     10,000      100.00

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