Frequencies for first 10,000 rows of comstat7 variable in nhamcsopd2010 dataset :

composition status |
              code |      Freq.     Percent        Cum.
-------------------+-----------------------------------
single entity drug |      1,269       12.69       12.69
  combination drug |        111        1.11       13.80
      undetermined |         20        0.20       14.00
                 . |      8,600       86.00      100.00
-------------------+-----------------------------------
             Total |     10,000      100.00

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