Frequencies for first 10,000 rows of drg1ing4 variable in nhamcsed2005 dataset :

                             ing. #4 |      Freq.     Percent        Cum.
-------------------------------------+-----------------------------------
                          boric acid |          1        0.01        0.01
                          ichthammol |          1        0.01        0.02
                          phenacetin |          2        0.02        0.04
                       potassium ion |         12        0.12        0.16
                          riboflavin |          3        0.03        0.19
                      sodium sulfate |          3        0.03        0.22
                            thiamine |          9        0.09        0.31
   zinc topical agents, external use |          2        0.02        0.33
                          zinc oxide |          1        0.01        0.34
                    atropine sulfate |          3        0.03        0.37
              hydrocortisone acetate |          3        0.03        0.40
                 hyoscyamine sulfate |          8        0.08        0.48
                doxylamine succinate |          1        0.01        0.49
                                   . |      9,951       99.51      100.00
-------------------------------------+-----------------------------------
                               Total |     10,000      100.00

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