(Reuters) - Chicago Federal Reserve President Charles Evans on Thursday said he is nervous about too-low inflation. A burst of inflation for six months “is not nearly enough... patience is something we are going to have to grapple with, probably,” Evans told reporters on a call. “We should be comfortable with a sustainable 2.5% inflation rate for a year; I don’t really get nervous until it starts creeping up to 3%, and even then, I’d like to know how that’s how that’s being achieved.”