Frequencies for first 10,000 rows of comstat1 variable in namcs2007 dataset :

composition status |
              code |      Freq.     Percent        Cum.
-------------------+-----------------------------------
single entity drug |      6,406       64.06       64.06
  combination drug |      1,292       12.92       76.98
      undetermined |          1        0.01       76.99
                 . |      2,301       23.01      100.00
-------------------+-----------------------------------
             Total |     10,000      100.00

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