Frequencies for first 10,000 rows of rx1v2c3 variable in nhamcsed2006 dataset :

        for rx1, level 2 of multum drug |
                            category #3 |      Freq.     Percent        Cum.
----------------------------------------+-----------------------------------
cns: antiemetic/antivertigo agents: 5ht |        126        1.26        1.26
                 hormones: sex hormones |          3        0.03        1.29
miscellaneous agents: genitourinary tra |          1        0.01        1.30
    respiratory agents: bronchodilators |         20        0.20        1.50
                                      . |      9,850       98.50      100.00
----------------------------------------+-----------------------------------
                                  Total |     10,000      100.00

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