What will it take to get to $300,000 in your 401(k)?

So do you have $300,000 or more in your 401(k)?

The average 401(k) plan balance hit $305,900 as of the second quarter among participants who have been in their 401(k) plan for 10 years in a row, according to the latest quarterly analysis of retirement savings trends released by Fidelity Investments. The average is based on a group of 1.6 million participants in Fidelity retirement accounts.

What is interesting: The latest average is more than five times the average balance of $59,900 for a similar group 10 years ago.

A big bull market for stocks, which began in March 2009 and has kept going, surely helps.

Who's doing well in their 401(k) plans?

Six-figure 401(k)s tend to be concentrated by ages for those who have been consistently saving in their 401(k) for 10 years straight.

For baby boomers in that group, who are ages 55 through 73 now, the average balance was $365,800 (with 697,000 Fidelity participants). For the Gen-Xers (ages 39 through 54), the average 10-year balance was $278,600 (with 802,000 in that group).

Overall, the average 401(k) balance was $106,000 based on 17.1 million Fidelity accounts in the second quarter. That was up about 1.9% from the second quarter in 2018.

Much of the big excitement, of course, is triggered by the notion that some people are actually hitting a million bucks in retirement savings.

An all-time high of 196,000 people had $1 million or more in their 401(k) plans in the second quarter. That's up from 180,000 at the end of the first quarter.

Most of the millionaires are baby boomers who are making decent money and they are aggressive savers who have consistently been saving for decades.

What will it take to get you to save more?

Adults ages 45 to 59 tend to feel they are on track if they have at least $250,000 saved, according to research by the Federal Reserve.

A lot of data regarding savings is downright discouraging. Some work at jobs that don't offer any kind of retirement savings plans.

When people talk about significantly smaller average balances, they are including younger people who haven't been on the job for long.

Yet when workers save for a decade, said Fidelity Vice President Katie Taylor, they have been able to build up to a more substantial nest egg as they move closer to retirement age.

Taylor noted that employees can benefit by increasing their contributions, as a percentage of pay, each year.

The bulk of that added savings took place because some employers will automatically increase the employee's own contributions over time. Yet 40% of the employees boosted their savings on their own.

Nearly two-thirds of workers between ages 26 and 64 are participating in 401(k) plans either directly or through a spouse, according to a study released in August by the Investment Company Institute (ICI).

When most people watch the wild swings on Wall Street these days, they are doing so because they are concerned about what could happen to the big number on their 401(k) statements.

At year-end 2016, data indicate that more than nine in 10 participants in 401(k) plans held at least some stocks through their plans, according to research by ICI.

Nearly half of those savers had more than 80% of their 401(k) plan account balance invested in stocks. Just 8% of 401(k) participants had nothing in stocks, according to that research.

What's holding people back? The usual suspects:

Student loan debt. Borrowing money from a 401(k) plan. Lack of cash and commitment.

Just because someone isn't saving in a retirement plan today doesn't mean they can't or won't change course later in their careers. Some may rationally choose to delay saving for retirement until they are earning more money or have taken care of other priorities, such as buying a home, according to the ICI research.

For younger savers the 401(k) is often the main source of investing. Millennial households owning mutual funds are more likely to hold funds only inside employer-sponsored retirement plans, according to ICI data.