Frequencies for first 10,000 rows of rx4v1c2 variable in nhamcsed2006 dataset :

   for rx4, level 1 of multum |
             drug category #2 |      Freq.     Percent        Cum.
------------------------------+-----------------------------------
              anti-infectives |         21        0.21        0.21
        cardiovascular agents |         17        0.17        0.38
central nervous system agents |         86        0.86        1.24
        coagulation modifiers |          7        0.07        1.31
         miscellaneous agents |         15        0.15        1.46
         nutritional products |          4        0.04        1.50
           respiratory agents |         51        0.51        2.01
               topical agents |          6        0.06        2.07
     psychotherapeutic agents |          5        0.05        2.12
                            . |      9,788       97.88      100.00
------------------------------+-----------------------------------
                        Total |     10,000      100.00

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