I like that last statement, if you give them idea if how much you are earning then the obligation for paying bills will be the next thing that you'll see coming, if they have the idea then they will put more for your monthly or sometimes even the daily as you are in the house and they'll think that you need to help, sometimes it's best not to let them know and just give whatever you can afford to help, in terms of other concern it will be on you if you want to share and if how vocal you are from your family.
It is better tell them the exact amount you are earning I total I agree with you because the moment they know they will just want to shift everything to you and that is not going to favor you because you will be dependent on even with you own money again they will always want you to do more than them financially because they might feel you have little money problems and if not for the selfish interest of people why will you think because someone is earning well the person does not have a problem. Even people that we look up to that we think are rich have their own problems. As far as you are working and you are in the house they will want you to contribute but when they don't know what you are earning they won't be able to ask for much and that is why keeping the amount I better.
And I know that their are people that even their wife don't even know the amount of money they are earning just because of the nature that women have of always wanting to spend because no matter the amount you leave for a woman they are still going to spend it and that is why we have to be very careful of the kind of information we are leaking out especially if we have a good job, they might been having a feeling that it going to huge but they won't be able to ask how much is your pay, as far they can ask then I have to keep it to my self, since am the one doing the work it is best known to me.