Frequencies for first 10,000 rows of comstat5 variable in namcs2007 dataset :

composition status |
              code |      Freq.     Percent        Cum.
-------------------+-----------------------------------
single entity drug |      1,607       16.07       16.07
  combination drug |        160        1.60       17.67
      undetermined |          2        0.02       17.69
                 . |      8,231       82.31      100.00
-------------------+-----------------------------------
             Total |     10,000      100.00

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