Frequencies for first 10,000 rows of comstat3 variable in nhamcsopd2010 dataset :

composition status |
              code |      Freq.     Percent        Cum.
-------------------+-----------------------------------
single entity drug |      3,416       34.16       34.16
  combination drug |        360        3.60       37.76
      undetermined |         53        0.53       38.29
                 . |      6,171       61.71      100.00
-------------------+-----------------------------------
             Total |     10,000      100.00

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