Frequencies for first 10,000 rows of comstat8 variable in nhamcsopd2005 dataset :

composition status |
   code for med #8 |      Freq.     Percent        Cum.
-------------------+-----------------------------------
single entity drug |        365        3.65        3.65
  combination drug |         41        0.41        4.06
      undetermined |          7        0.07        4.13
                 . |      9,587       95.87      100.00
-------------------+-----------------------------------
             Total |     10,000      100.00

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