Frequencies for first 10,000 rows of comstat4 variable in nhamcsopd2008 dataset :

          for rx4, |
composition status |
              code |      Freq.     Percent        Cum.
-------------------+-----------------------------------
single entity drug |      2,457       24.57       24.57
  combination drug |        251        2.51       27.08
      undetermined |          1        0.01       27.09
                 . |      7,291       72.91      100.00
-------------------+-----------------------------------
             Total |     10,000      100.00

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