Frequencies for first 10,000 rows of comstat1 variable in nhamcsopd2010 dataset :

composition status |
              code |      Freq.     Percent        Cum.
-------------------+-----------------------------------
single entity drug |      5,848       58.48       58.48
  combination drug |      1,139       11.39       69.87
      undetermined |        139        1.39       71.26
                 . |      2,874       28.74      100.00
-------------------+-----------------------------------
             Total |     10,000      100.00

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