Frequencies for first 10,000 rows of rx2v2c3 variable in nhamcsed2006 dataset :

        for rx2, level 2 of multum drug |
                            category #3 |      Freq.     Percent        Cum.
----------------------------------------+-----------------------------------
                   cns: anticonvulsants |          1        0.01        0.01
cns: antiemetic/antivertigo agents: 5ht |         75        0.75        0.76
miscellaneous agents: genitourinary tra |          3        0.03        0.79
    respiratory agents: bronchodilators |         16        0.16        0.95
                                      . |      9,905       99.05      100.00
----------------------------------------+-----------------------------------
                                  Total |     10,000      100.00

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