Frequencies for first 10,000 rows of rx4v2c3 variable in nhamcsed2006 dataset :

        for rx4, level 2 of multum drug |
                            category #3 |      Freq.     Percent        Cum.
----------------------------------------+-----------------------------------
                   cns: anticonvulsants |          1        0.01        0.01
cns: antiemetic/antivertigo agents: 5ht |         15        0.15        0.16
miscellaneous agents: genitourinary tra |          2        0.02        0.18
    respiratory agents: bronchodilators |          6        0.06        0.24
   miscellaneous agents: antipsoriatics |          1        0.01        0.25
                                      . |      9,975       99.75      100.00
----------------------------------------+-----------------------------------
                                  Total |     10,000      100.00

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