Frequencies for first 10,000 rows of rx3v1c2 variable in nhamcsopd2006 dataset :

   for rx3, level 1 of multum |
             drug category #2 |      Freq.     Percent        Cum.
------------------------------+-----------------------------------
              Anti-infectives |         21        0.21        0.21
              Antineoplastics |          1        0.01        0.22
        Cardiovascular agents |         14        0.14        0.36
Central nervous system agents |        103        1.03        1.39
        Coagulation modifiers |         72        0.72        2.11
      Gastrointestinal agents |          1        0.01        2.12
                     Hormones |         16        0.16        2.28
         Miscellaneous agents |         56        0.56        2.84
         Nutritional products |          8        0.08        2.92
           Respiratory agents |         42        0.42        3.34
               Topical agents |         19        0.19        3.53
     Psychotherapeutic agents |          8        0.08        3.61
             Metabolic agents |         10        0.10        3.71
                            . |      9,629       96.29      100.00
------------------------------+-----------------------------------
                        Total |     10,000      100.00

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