Frequencies for first 10,000 rows of comstat5 variable in nhamcsopd2007 dataset :

          for rx5, |
composition status |
              code |      Freq.     Percent        Cum.
-------------------+-----------------------------------
single entity drug |      1,767       17.67       17.67
  combination drug |        167        1.67       19.34
                 . |      8,066       80.66      100.00
-------------------+-----------------------------------
             Total |     10,000      100.00

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