Frequencies for first 10,000 rows of prescr3 variable in nhamcsed2005 dataset :

 prescription status |
                code |      Freq.     Percent        Cum.
---------------------+-----------------------------------
   prescription drug |      2,030       20.30       20.30
nonprescription drug |        371        3.71       24.01
        undetermined |        282        2.82       26.83
                   . |      7,317       73.17      100.00
---------------------+-----------------------------------
               Total |     10,000      100.00

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