Just how well have 401(k) investors fared over the recent years?

Updated research from the non-profit Employee Benefits Research Institute, a leading analyst of the defined contribution market, shows that savers who have been in the same plan since 2007 are making out quite well.

The new data differentiates participants in the EBRI database that have consistently stayed invested in one 401(k) plan since at least 2007.

That database, which was designed in conjunction with the Investment Company Institute, tracks about 26.4 million participants.

About 19 percent, or 4.2 million of those participants held the same 401(k) account between the end of 2007 and the end of 2013. The EBRI/ICI analysts call them “consistent” participants.

The new report shows that consistency is clearly paying dividends.

By the end of 2013, the consistent cohort had accrued larger account balances when compared to the overall cross-section of participants in the database.

Nearly a quarter, or 23.5 percent of consistent participants had more than $200,000 in their 401(k) accounts at the end of the six-year period tracked, while only 10 percent in the overall database had as much.

Another 18.8 percent of consistent participants had amassed between $100,000 and $200,000, compared to the 9.6 percent in the overall database.

After six years of consistent participation, the average account balance was $148,399, more than twice the average balance of $72,383 in the entire database.

The median balance was $75,359 with consistent participants, more than four times the median balance of the entire accounts tracked, which was $18,433.

Overall, average balances of consistent savers experienced a 10.9 percent rate of annual compound growth between 2007 and 2013, in spite of the massive losses in 2008, when the average 401(k) balance fell more than 25 percent.

Those increases blow away the annual gains experienced by the rest of the database. For all participants, the average balance was about $64,000 in 2007. By 2013, that average had only grown about $7,000, to an average of $72,383.

How is the group of consistent participants demographically distinct?

For one, they are older. By the end of 2013, only 2 percent were in their 20s and only 18 percent were in their 30s.

And 36 percent of the consistent group was in its 50s, while 14 percent were in their 60s.

Far more younger participants are represented in the entire database, as 13 percent of all participants are in their 20s, and 23 percent are in their 30s.

Clearly, age benefits the account values of older participants. So does staying with the same employer.

In the consistent group, 42 percent of participants had 10 to 20 years of tenure with their existing employer, and 29 percent had more than 20 years.

In the overall database, 37 percent had five or fewer years of tenure.

The new study complements the EBRI/ICI’s annual analysis of its database, which was last updated at the end of 2014.

Focusing a study on the accounts of consistent participants allows for a “more meaningful analysis of the potential for 401(k) participants to accumulate retirement assets over time,” according to a release from the EBRI.