Frequencies for first 10,000 rows of prescr3 variable in nhamcsed2012 dataset :

        Prescription status code for |
                       medication #3 |      Freq.     Percent        Cum.
-------------------------------------+-----------------------------------
                   Prescription drug |      1,993       19.93       19.93
                Nonprescription drug |         64        0.64       20.57
                        Undetermined |         49        0.49       21.06
Prescription or Nonprescription drug |      1,003       10.03       31.09
                                   . |      6,891       68.91      100.00
-------------------------------------+-----------------------------------
                               Total |     10,000      100.00

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