Frequencies for first 10,000 rows of rx7v1c2 variable in nhamcsopd2006 dataset :

   for rx7, level 1 of multum |
             drug category #2 |      Freq.     Percent        Cum.
------------------------------+-----------------------------------
              Anti-infectives |          5        0.05        0.05
        Cardiovascular agents |         11        0.11        0.16
Central nervous system agents |         17        0.17        0.33
        Coagulation modifiers |         31        0.31        0.64
                     Hormones |          7        0.07        0.71
         Miscellaneous agents |          8        0.08        0.79
         Nutritional products |          6        0.06        0.85
           Respiratory agents |          7        0.07        0.92
               Topical agents |          7        0.07        0.99
        Alternative medicines |          1        0.01        1.00
     Psychotherapeutic agents |          1        0.01        1.01
             Metabolic agents |          4        0.04        1.05
                            . |      9,895       98.95      100.00
------------------------------+-----------------------------------
                        Total |     10,000      100.00

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