Frequencies for first 10,000 rows of comstat4 variable in nhamcsopd2007 dataset :

          for rx4, |
composition status |
              code |      Freq.     Percent        Cum.
-------------------+-----------------------------------
single entity drug |      2,284       22.84       22.84
  combination drug |        203        2.03       24.87
                 . |      7,513       75.13      100.00
-------------------+-----------------------------------
             Total |     10,000      100.00

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