Frequencies for first 10,000 rows of comstat1 variable in nhamcsopd2008 dataset :

          for rx1, |
composition status |
              code |      Freq.     Percent        Cum.
-------------------+-----------------------------------
single entity drug |      5,960       59.60       59.60
  combination drug |      1,137       11.37       70.97
      undetermined |          2        0.02       70.99
                 . |      2,901       29.01      100.00
-------------------+-----------------------------------
             Total |     10,000      100.00

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