Long-term U.S. mortgage rates leaped this week to their highest levels in seven years amid global anxiety over rising interest rates that has gripped financial markets. Costs for would-be homebuyers are climbing. Mortgage buyer Freddie Mac said Thursday the rate on 30-year, fixed-rate mortgages jumped to an average 4.90 percent this week from 4.71 percent last week. That's the highest level for the...