Frequencies for first 10,000 rows of prescr4 variable in nhamcsopd2006 dataset :

            for rx4, |
 prescription status |
                code |      Freq.     Percent        Cum.
---------------------+-----------------------------------
   Prescription drug |      1,649       16.49       16.49
Nonprescription drug |        216        2.16       18.65
        Undetermined |        155        1.55       20.20
                   . |      7,980       79.80      100.00
---------------------+-----------------------------------
               Total |     10,000      100.00

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