Frequencies for first 10,000 rows of comstat3 variable in namcs2007 dataset :

composition status |
              code |      Freq.     Percent        Cum.
-------------------+-----------------------------------
single entity drug |      3,052       30.52       30.52
  combination drug |        413        4.13       34.65
      undetermined |          2        0.02       34.67
                 . |      6,533       65.33      100.00
-------------------+-----------------------------------
             Total |     10,000      100.00

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