Know what you are worth and give a range in dollar or percentage increase. It should be based on current/previous salary which you will have to disclose eventually.
Unless jumping to a higher title, an offer is made based on a reasonable increase from current salary and positions market value. Not your own perceived value. No need to elaborate your market value. A direct answer works the best.
As a hiring manager, I eliminate anyone who wouldn't give a ballpark of what they looking for no matter how pretty the resume is.
