table_alt               A function to explore response alternatives in
                        a data frame
table_non_resp          A function that return proportion of missing
                        values in a data frame
table_non_resp_2        A function that return absolute vaules of
                        missing values in a data frame
table_unga              A function for cross tabulation.
table_unga_general      Function to cross tabulate all variables in a
                        data frame
