Frequencies for first 10,000 rows of prescr18 variable in nhamcsed2015 dataset 

        Prescription status code for |
                      medication #18 |      Freq.     Percent        Cum.
-------------------------------------+-----------------------------------
                   Prescription drug |         30        0.30        0.30
                        Undetermined |          2        0.02        0.32
Prescription or Nonprescription drug |         10        0.10        0.42
                                   . |      9,958       99.58      100.00
-------------------------------------+-----------------------------------
                               Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 20 Nov 2017