Frequencies for first 10,000 rows of prescr3 variable in namcs2007 dataset :

 prescription status |
                code |      Freq.     Percent        Cum.
---------------------+-----------------------------------
   prescription drug |      3,119       31.19       31.19
nonprescription drug |        257        2.57       33.76
        undetermined |         90        0.90       34.66
             illicit |          1        0.01       34.67
                   . |      6,533       65.33      100.00
---------------------+-----------------------------------
               Total |     10,000      100.00

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