Over 250 U.S. mail processing centers and slow first-class delivery are on the chopping block for next spring due to steadily declining mail volume, according to the Postal Service.  At a news briefing Monday, postal vice president David Williams said the move will eliminate the chance for stamped letters to arrive the next day to help avert possible bankruptcy next year.  He states, the postal service is not “writing off first class mail” but that it must respond to new market realities in which people are turning more to the Internet for email communications and bill payment.  After reaching a peak in 2006, first-class mail volume is now at 78 million. It is projected to drop by roughly half by 2020.