As they struggle to save for retirement, a growing number of middle-class Americans plan to postpone their golden years until they are in their 80's. Nearly one-third, or 30%, now plan to work until they are 80 or older -- up from 25% a year ago, according to a Wells Fargo survey of 1,000 adults with income less than $100,000. "It is so tough for Americans to save for retirement that the answer seems to be to work longer," said Joe Ready, director of Wells Fargo Institutional Retirement and Trust.