only cos had century of women earning less than men for the same job? probably still do...
I know what you mean, is sort of rude to ask, I guess in normal life you would question why they want to know.
Really annoys me when those surveys take ages to do and you wish hadn't started. Then right at the end they ask age bracket, have you any kids, how much do you earn - is nothing to do with the original purpose of survey... some won't let you progress without filling in a field - so bet a lot end up lying.
Be interesting to make out earned megabucks and see what spam you got lol