Frequencies for first 10,000 rows of rx2v2c3 variable in nhamcsopd2006 dataset :

        for rx2, level 2 of multum drug |
                            category #3 |      Freq.     Percent        Cum.
----------------------------------------+-----------------------------------
CNS: Antiemetic/antivertigo agents: 5HT |         26        0.26        0.26
                 Hormones: sex hormones |         11        0.11        0.37
    Respiratory agents: bronchodilators |          1        0.01        0.38
   Miscellaneous agents: antipsoriatics |          9        0.09        0.47
                                      . |      9,953       99.53      100.00
----------------------------------------+-----------------------------------
                                  Total |     10,000      100.00

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