Frequencies for first 10,000 rows of rx3v2c3 variable in nhamcsopd2006 dataset :

        for rx3, level 2 of multum drug |
                            category #3 |      Freq.     Percent        Cum.
----------------------------------------+-----------------------------------
CNS: Antiemetic/antivertigo agents: 5HT |         17        0.17        0.17
                 Hormones: sex hormones |          4        0.04        0.21
    Respiratory agents: bronchodilators |          2        0.02        0.23
   Miscellaneous agents: antipsoriatics |          4        0.04        0.27
                                      . |      9,973       99.73      100.00
----------------------------------------+-----------------------------------
                                  Total |     10,000      100.00

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