Frequencies for first 10,000 rows of prescr3 variable in nhamcsopd2007 dataset :

            for rx3, |
 prescription status |
                code |      Freq.     Percent        Cum.
---------------------+-----------------------------------
   prescription drug |      2,929       29.29       29.29
nonprescription drug |        326        3.26       32.55
        undetermined |         98        0.98       33.53
                   . |      6,647       66.47      100.00
---------------------+-----------------------------------
               Total |     10,000      100.00

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