Frequencies for first 10,000 rows of rx5v2c3 variable in nhamcsed2006 dataset :

        for rx5, level 2 of multum drug |
                            category #3 |      Freq.     Percent        Cum.
----------------------------------------+-----------------------------------
                   cns: anticonvulsants |          2        0.02        0.02
cns: antiemetic/antivertigo agents: 5ht |          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