Frequencies for first 10,000 rows of rx1v1c1 variable in nhamcsopd2006 dataset :

   for rx1, level 1 of multum |
             drug category #1 |      Freq.     Percent        Cum.
------------------------------+-----------------------------------
              Anti-infectives |        773        7.73        7.73
              Antineoplastics |        156        1.56        9.29
                  Biologicals |         13        0.13        9.42
        Cardiovascular agents |        638        6.38       15.80
Central nervous system agents |      1,441       14.41       30.21
        Coagulation modifiers |        193        1.93       32.14
      Gastrointestinal agents |        300        3.00       35.14
                     Hormones |        391        3.91       39.05
         Miscellaneous agents |        142        1.42       40.47
         Nutritional products |        509        5.09       45.56
           Respiratory agents |        448        4.48       50.04
               Topical agents |        543        5.43       55.47
        Alternative medicines |          7        0.07       55.54
     Psychotherapeutic agents |        577        5.77       61.31
         Immunological agents |        241        2.41       63.72
            Radiologic agents |          5        0.05       63.77
             Metabolic agents |        299        2.99       66.76
           Pharmaceutical aid |          4        0.04       66.80
                            . |      3,320       33.20      100.00
------------------------------+-----------------------------------
                        Total |     10,000      100.00

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