Frequencies for first 10,000 rows of comstat4 variable in nhamcsed2008 dataset :

          for rx4, |
composition status |
              code |      Freq.     Percent        Cum.
-------------------+-----------------------------------
single entity drug |      1,386       13.86       13.86
  combination drug |        275        2.75       16.61
      undetermined |          1        0.01       16.62
                 . |      8,338       83.38      100.00
-------------------+-----------------------------------
             Total |     10,000      100.00

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