Frequencies for first 10,000 rows of rx7v1c1 variable in nhamcsopd2006 dataset :

   for rx7, level 1 of multum |
             drug category #1 |      Freq.     Percent        Cum.
------------------------------+-----------------------------------
              Anti-infectives |         33        0.33        0.33
              Antineoplastics |          6        0.06        0.39
                  Biologicals |          1        0.01        0.40
        Cardiovascular agents |        122        1.22        1.62
Central nervous system agents |        160        1.60        3.22
        Coagulation modifiers |         18        0.18        3.40
      Gastrointestinal agents |         85        0.85        4.25
                     Hormones |         32        0.32        4.57
         Miscellaneous agents |         14        0.14        4.71
         Nutritional products |         77        0.77        5.48
           Respiratory agents |         56        0.56        6.04
               Topical agents |         29        0.29        6.33
        Alternative medicines |         17        0.17        6.50
     Psychotherapeutic agents |         41        0.41        6.91
         Immunological agents |          9        0.09        7.00
            Radiologic agents |          3        0.03        7.03
             Metabolic agents |         74        0.74        7.77
                            . |      9,223       92.23      100.00
------------------------------+-----------------------------------
                        Total |     10,000      100.00

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