Frequencies for first 10,000 rows of comstat2 variable in namcs2010 dataset :

composition status |
              code |      Freq.     Percent        Cum.
-------------------+-----------------------------------
single entity drug |      4,689       46.89       46.89
  combination drug |        722        7.22       54.11
      undetermined |         78        0.78       54.89
                 . |      4,511       45.11      100.00
-------------------+-----------------------------------
             Total |     10,000      100.00

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