NEW YORK (MainStreet) — You're doing everything the experts recommend. Deferring a chunk of your salary to your 401(k) at work, at least up to the company match, attending the educational seminars, investing in a diversified portfolio – what else can you do to secure your future retirement? The one thing more than a third of Americans with a 401(k) have never done: increase the amount they automatically contribute.

Read More: Companies Lag in Matching 401(k) Programs

A new TIAA-CREF survey says that while many of us have never raised our deferral, 26% have not kicked-up what they kick-in in over a year. With 44% of the U.S. workforce saving 10% or less of their annual income for retirement, that's a problem. Many financial advisors say we should be putting aside 10-15% -- even more as we age.

One of the best times to increase your contribution is when you get a raise. Most of us (57%) don't do that. More men (33%) than women (17%) are likely to be contributing the maximum amount allowed -- and thrifty Millennials are most likely (52%) to jack up their contribution after a bump in pay.

Many of us set-it-and-forget-it when it comes to our 401(k) – and that's a good thing if we're properly invested. One-quarter (25%) of workers have never made changes to their investments. If you're in that crowd, it might be a good idea to have an advisor check your allocation, just so you can ignore it with confidence.

But the workers really lagging behind are those who never got started. More than half (53%) of employees who work for a company offering a 401(k) retirement plan were not automatically enrolled in their companies' plans, according to the survey.

Failing to sign up right out of the gate means time is not on your side. In fact, more than a third (37%) of respondents who were not automatically enrolled in their at-work retirement plan said they waited six months or longer to enroll – nearly one quarter (24%) waited a year or more.

--Written by Hal M. Bundrick for MainStreet