Other than salary, I don't mind sharing other information such as phone bills etc. I mean what can they do if they know my phone bill, electricity bill, etc. etc. etc.
It is not about what they can or cannot do with the information. Privacy bhee koi cheez hoti hay >
Instead of asking those questions directly , if they are in the form of an annonymous poll it is fine .
Like I opened a Poll in AV about the age question. It was annonymous nobody knew who is voting in which group.
Similar poll can be conducted for phone bill , with ranges.