Frequencies for first 10,000 rows of comstat5 variable in nhamcsopd2005 dataset :

composition status |
   code for med #5 |      Freq.     Percent        Cum.
-------------------+-----------------------------------
single entity drug |      1,069       10.69       10.69
  combination drug |        107        1.07       11.76
      undetermined |         13        0.13       11.89
                 . |      8,811       88.11      100.00
-------------------+-----------------------------------
             Total |     10,000      100.00

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