Mortgage rates did something unexpected over the past week - they actually increased. Average rates on 30-year home loans nationwide rose to 5.12 percent, from an all-time low of 4.96 percent the prior week, mortgage company Freddie Mac reported. The average rate on 15-year fixed-rate mortgages also was higher, rising to 4.8 percent from 4.65 percent the week before. Experts say those who are buying a home or refinancing who haven't yet locked in a rate shouldn't worry too much, though. There is hardly anything at all that would suggest that rates will increase by any significant amount anytime soon. As a general rule, bad economic news equals low mortgage rates (an oversimplification, but one that's pretty accurate). And we'll probably continue to have bad economic news for some time.