Frequencies for first 10,000 rows of comstat7 variable in nhamcsed2008 dataset :

          for rx7, |
composition status |
              code |      Freq.     Percent        Cum.
-------------------+-----------------------------------
single entity drug |        223        2.23        2.23
  combination drug |         36        0.36        2.59
                 . |      9,741       97.41      100.00
-------------------+-----------------------------------
             Total |     10,000      100.00

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