Frequencies for first 10,000 rows of prescr2 variable in nhamcsopd2007 dataset :

            for rx2, |
 prescription status |
                code |      Freq.     Percent        Cum.
---------------------+-----------------------------------
   prescription drug |      3,985       39.85       39.85
nonprescription drug |        576        5.76       45.61
        undetermined |        112        1.12       46.73
                   . |      5,327       53.27      100.00
---------------------+-----------------------------------
               Total |     10,000      100.00

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