Frequencies for first 10,000 rows of drg4ing5 variable in nhamcsed2005 dataset :

                             ing. #5 |      Freq.     Percent        Cum.
-------------------------------------+-----------------------------------
                          sodium ion |          2        0.02        0.02
                           vitamin a |          3        0.03        0.05
                  potassium chloride |          1        0.01        0.06
                    neomycin sulfate |          1        0.01        0.07
                                   . |      9,993       99.93      100.00
-------------------------------------+-----------------------------------
                               Total |     10,000      100.00

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