Frequencies for first 10,000 rows of comstat1 variable in nhamcsopd2006 dataset :

          for rx1, |
composition status |
              code |      Freq.     Percent        Cum.
-------------------+-----------------------------------
Single entity drug |      5,518       55.18       55.18
  Combination drug |      1,162       11.62       66.80
                 . |      3,320       33.20      100.00
-------------------+-----------------------------------
             Total |     10,000      100.00

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