Frequencies for first 10,000 rows of rx8v1c2 variable in nhamcsopd2006 dataset :

   for rx8, level 1 of multum |
             drug category #2 |      Freq.     Percent        Cum.
------------------------------+-----------------------------------
              Anti-infectives |          3        0.03        0.03
        Cardiovascular agents |         13        0.13        0.16
Central nervous system agents |         18        0.18        0.34
        Coagulation modifiers |         17        0.17        0.51
                     Hormones |          1        0.01        0.52
         Miscellaneous agents |          9        0.09        0.61
         Nutritional products |          4        0.04        0.65
           Respiratory agents |          5        0.05        0.70
               Topical agents |          1        0.01        0.71
        Alternative medicines |          1        0.01        0.72
             Metabolic agents |          3        0.03        0.75
                            . |      9,925       99.25      100.00
------------------------------+-----------------------------------
                        Total |     10,000      100.00

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