Frequencies for first 10,000 rows of rx6v1c2 variable in nhamcsed2006 dataset :

   for rx6, level 1 of multum |
             drug category #2 |      Freq.     Percent        Cum.
------------------------------+-----------------------------------
              anti-infectives |          4        0.04        0.04
        cardiovascular agents |          5        0.05        0.09
central nervous system agents |         16        0.16        0.25
        coagulation modifiers |          6        0.06        0.31
         miscellaneous agents |          2        0.02        0.33
         nutritional products |          4        0.04        0.37
           respiratory agents |         11        0.11        0.48
               topical agents |          3        0.03        0.51
     psychotherapeutic agents |          3        0.03        0.54
                            . |      9,946       99.46      100.00
------------------------------+-----------------------------------
                        Total |     10,000      100.00

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