Frequencies for first 10,000 rows of comstat3 variable in nhamcsopd2006 dataset :

          for rx3, |
composition status |
              code |      Freq.     Percent        Cum.
-------------------+-----------------------------------
Single entity drug |      2,597       25.97       25.97
  Combination drug |        344        3.44       29.41
                 . |      7,059       70.59      100.00
-------------------+-----------------------------------
             Total |     10,000      100.00

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