Frequencies for first 10,000 rows of comstat3 variable in namcs2010 dataset :

composition status |
              code |      Freq.     Percent        Cum.
-------------------+-----------------------------------
single entity drug |      3,385       33.85       33.85
  combination drug |        463        4.63       38.48
      undetermined |         52        0.52       39.00
                 . |      6,100       61.00      100.00
-------------------+-----------------------------------
             Total |     10,000      100.00

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