From more immediate financial help, like credit advice and childcare services, to personalized investment guidance from a professional, employers can now give employees what they want (and boost retention too).

The bill's sponsors estimate a modest diversification into "alts," including real estate and private equity, could boost 401(k) performance by 17% a year and cut losses in a recession.

High spenders including the U.S. didn't rank as highly as their expenditures might indicate.

While the inflation-fueled increase is much-needed for retirees, some experts say it is still inadequate in light of skyrocketing housing and health care costs.