You have to play the game a little. Add up your salary, other compensation (options), a markup for how big a pita changing jobs is, cost of living in the new area of applicable. Then throw that away and mark up to the number that you actually want. Pick something that you think is silly high. Don't say "my current salary is 90,000" say "I would like to make 170,000". You didn't tell them your salary/total comp, but you answered the question and you anchored to a higher value.