Before you respond to these queries from prospective employers, you better understand why they seek this information.
Employers seek this information to gauge your market value and also want to know how much you will be expecting from them. If your salary history shows that the potential employer doesn't have a budget to afford you, he will not like to waste time on further discussions.
Play your cards right: Your salary history gives the hiring manager an advantage while negotiating your salary. The best way to turn the negotiating process to your advantage is to avoid giving the salary history in the written application. Just send the resume. In such a situation, you can ask the employer about the range he is willing to offer you.
Pitfalls: This strategy has some pitfalls. You may not be called if you don't give your salary history. If you are a qualified candidate and they ignore you because you have not given them your salary information, you better not to choose to work with them. Simply telling the employer of your expectations may not work.
Tell the truth: The prospective employers want to check whether you will be satisfied with what you are offered. They also want to see whether you had received hikes whenever you changed jobs. In a way, it won't be a problem if you give this information to the hiring companies. Give full information about your pay package that may include bonuses, commissions, stock options or any other perks. This, in fact, may go in your favor and you may get more than what you expect.