Frequencies for first 10,000 rows of comstat6 variable in nhamcsopd2010 dataset :

composition status |
              code |      Freq.     Percent        Cum.
-------------------+-----------------------------------
single entity drug |      1,654       16.54       16.54
  combination drug |        149        1.49       18.03
      undetermined |         23        0.23       18.26
                 . |      8,174       81.74      100.00
-------------------+-----------------------------------
             Total |     10,000      100.00

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