The percentage of your annual salary that you put into savings for retirement might be lower than you think, so long as you’re willing to spend a few extra years in the office. A recent study from Boston College, called “How Much to Save for a Secure Retirement,” finds that 45-year-olds with medium earnings need to save just 18 percent of their salary to maintain their lifestyle in retirement. The catch? They must work until age 70. “Retiring later,” the report states “is an incredibly powerful lever.” At age 70, social security benefits are more than 70 percent higher than they are at age 62, the earliest age at which most people can claim benefits. Postponing retirement also gives investments and 401(k) plans more time to grow.