Frequencies for first 10,000 rows of prescr4 variable in nhamcsopd2007 dataset :

            for rx4, |
 prescription status |
                code |      Freq.     Percent        Cum.
---------------------+-----------------------------------
   prescription drug |      2,155       21.55       21.55
nonprescription drug |        264        2.64       24.19
        undetermined |         67        0.67       24.86
             illicit |          1        0.01       24.87
                   . |      7,513       75.13      100.00
---------------------+-----------------------------------
               Total |     10,000      100.00

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