Frequencies for first 10,000 rows of prescr3 variable in nhamcsed2013 dataset :

        Prescription status code for |
                       medication #3 |      Freq.     Percent        Cum.
-------------------------------------+-----------------------------------
                   Prescription drug |      2,062       20.62       20.62
                Nonprescription drug |         94        0.94       21.56
                        Undetermined |         47        0.47       22.03
Prescription or Nonprescription drug |      1,100       11.00       33.03
                                   . |      6,697       66.97      100.00
-------------------------------------+-----------------------------------
                               Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 7 Nov 2016