More contributions and the Trump rally drove the average 401(k) balance to an all-time high last year of $92,500, up nearly 5 percent from 2015, according to Fidelity Investments, one of the largest providers of workplace retirement plans. That average balance has increased 33 percent from $69,400 in 2012.

Workers contributed an average of 8.4 percent of their salaries to the employer-sponsored plans last year, which is the highest level of contribution since before the financial crisis, Fidelity found. When you add in employer matching contributions, which average 3 percent of annual pay, and profit-sharing, which usually adds another 1 percent to contributions, the typical worker is saving 12.4 percent of their salary annually for retirement, said Katie Taylor, Fidelity's vice president of thought leadership.

She also attributed the gains in 401(k) balances to employers making it easier for workers to contribute to the plans through automatic enrollment as well as plans that automatically increase contributions for workers. About 70 percent of Fidelity's plans "auto-enroll" workers and roughly 16 percent of those plans increase worker contributions each year if they agree to it. A bull market also juiced contributions, "though people should be saving for retirement regardless of what the market is doing," Taylor said. Fidelity's analysis is based on more than 22,100 corporate retirement plans with 14.5 million participants.

Is it enough?