Frequencies for first 10,000 rows of rx2v1c2 variable in nhamcsopd2006 dataset :

   for rx2, level 1 of multum |
             drug category #2 |      Freq.     Percent        Cum.
------------------------------+-----------------------------------
              Anti-infectives |         45        0.45        0.45
        Cardiovascular agents |         11        0.11        0.56
Central nervous system agents |        152        1.52        2.08
        Coagulation modifiers |         60        0.60        2.68
      Gastrointestinal agents |          1        0.01        2.69
                     Hormones |         32        0.32        3.01
         Miscellaneous agents |        105        1.05        4.06
         Nutritional products |          4        0.04        4.10
           Respiratory agents |         63        0.63        4.73
               Topical agents |         26        0.26        4.99
        Alternative medicines |          2        0.02        5.01
     Psychotherapeutic agents |         11        0.11        5.12
             Metabolic agents |          7        0.07        5.19
                            . |      9,481       94.81      100.00
------------------------------+-----------------------------------
                        Total |     10,000      100.00

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