Frequencies for first 10,000 rows of comstat5 variable in nhamcsed2013 dataset :

Composition status |
code medication #5 |      Freq.     Percent        Cum.
-------------------+-----------------------------------
Single entity drug |      1,053       10.53       10.53
  Combination drug |        141        1.41       11.94
      Undetermined |         11        0.11       12.05
                 . |      8,795       87.95      100.00
-------------------+-----------------------------------
             Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 7 Nov 2016