Frequencies for first 10,000 rows of drug8cl3 variable in nhamcsed2005 dataset :

          ndc code #3 for medication #8 |      Freq.     Percent        Cum.
----------------------------------------+-----------------------------------
                cycloplegics/mydriatics |          1        0.01        0.01
         antiasthmatics/bronchodilators |          1        0.01        0.02
                         antihistamines |          3        0.03        0.05
                                      . |      9,995       99.95      100.00
----------------------------------------+-----------------------------------
                                  Total |     10,000      100.00

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