Frequencies for first 10,000 rows of prescr3 variable in nhamcsed2007 dataset :

            for rx3, |
 prescription status |
                code |      Freq.     Percent        Cum.
---------------------+-----------------------------------
   prescription drug |      2,502       25.02       25.02
nonprescription drug |        457        4.57       29.59
        undetermined |         62        0.62       30.21
                   . |      6,979       69.79      100.00
---------------------+-----------------------------------
               Total |     10,000      100.00

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