Frequencies for first 10,000 rows of rx4v2c3 variable in nhamcsopd2006 dataset :

        for rx4, level 2 of multum drug |
                            category #3 |      Freq.     Percent        Cum.
----------------------------------------+-----------------------------------
CNS: Antiemetic/antivertigo agents: 5HT |          4        0.04        0.04
                 Hormones: sex hormones |          1        0.01        0.05
Miscellaneous agents: genitourinary tra |          2        0.02        0.07
    Respiratory agents: bronchodilators |          1        0.01        0.08
   Miscellaneous agents: antipsoriatics |          5        0.05        0.13
                                      . |      9,987       99.87      100.00
----------------------------------------+-----------------------------------
                                  Total |     10,000      100.00

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