Dear Millennials: Start Saving 22% of Your Pay

If you're young and saving for retirement, you should plan to sock away nearly a quarter of your pay in your 401(k).

A recent survey from personal finance website NerdWallet found that a 25-year-old who is earning $40,000 a year will need to have saved 22 percent of pay in a retirement account over the course of his or her career in order to replace 80 percent of annual income by age 67.