Frequencies for first 10,000 rows of comstat4 variable in namcs2007 dataset :

composition status |
              code |      Freq.     Percent        Cum.
-------------------+-----------------------------------
single entity drug |      2,200       22.00       22.00
  combination drug |        234        2.34       24.34
                 . |      7,566       75.66      100.00
-------------------+-----------------------------------
             Total |     10,000      100.00

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