Frequencies for first 10,000 rows of comstat8 variable in nhamcsopd2010 dataset :

composition status |
              code |      Freq.     Percent        Cum.
-------------------+-----------------------------------
single entity drug |        928        9.28        9.28
  combination drug |         82        0.82       10.10
      undetermined |         19        0.19       10.29
                 . |      8,971       89.71      100.00
-------------------+-----------------------------------
             Total |     10,000      100.00

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