Just lie or if you want to be a stick in the mud put $0 in the field and tell them to buzz off. If they come back to you with "proof" that you had a lower sala

Just lie or if you want to be a stick in the mud put $0 in the field and tell them to buzz off. If they come back to you with "proof" that you had a lower salary just say that that didn't include your large yearly bonuses and that your previous salary was confidential anyway. If their background check comes with a much lower salary they'll probably doubt the agency anyway. This information is supposed to be pretty protected and most people are probably just doing the old trick where they pretend to be someone interested in a job at your former company and ask about general compensation there.