Frequencies for first 10,000 rows of comstat4 variable in nhamcsopd2003 dataset :

composition status |
          code for |
     medication #4 |      Freq.     Percent        Cum.
-------------------+-----------------------------------
single entity drug |      1,575       15.75       15.75
  combination drug |        142        1.42       17.17
      undetermined |         54        0.54       17.71
                 . |      8,229       82.29      100.00
-------------------+-----------------------------------
             Total |     10,000      100.00

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