Frequencies for first 10,000 rows of comstat3 variable in nhamcsopd2009 dataset :

          for rx3, |
composition status |
              code |      Freq.     Percent        Cum.
-------------------+-----------------------------------
single entity drug |      3,242       32.42       32.42
  combination drug |        316        3.16       35.58
      undetermined |         49        0.49       36.07
                 . |      6,393       63.93      100.00
-------------------+-----------------------------------
             Total |     10,000      100.00

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