WASHINGTON — Baltimore-based mutual fund company T. Rowe Price says the average employee pretax 401(k) deferral rate reached 8.3 percent, the highest in the 10 years T. Rowe Price has been tracking it.

More employers are switching to automatic contributions from employee checks, and the number of retirement plans with a 6 percent default deferral rate surpassed the number of plans with a 3 percent default rate, considered the industry standard, for the first time.

Auto-enrollment programs are also effective in getting employees to stay enrolled. T. Rowe Price says the average participation rate in auto-enrollment plans was over 42 percentage points higher than plans without auto-enrollment.

Almost one-in-four workers with a 401(k) have borrowed from it, but the 23.4 percent loan usage rate last year was a decline. The percentage of participants with multiple loans also decreased to 15.6 percent, down 4 percentage points from its peak in 2013.

“We continue to see the significant impact plan design and financial wellness programs have on participant behavior, as evidenced by the increase in both participation and deferral rates and decrease in loan usage,” said Aimee DeCamillo, head of T. Rowe Price Retirement Plan Services, Inc.

Almost all 401(k) plans now offer target-date funds, with plan sponsor adoption rising to 94 percent in 2017.

Target-date funds also accounted for the largest percentage of plan assets under management, surpassing all other investment types last year.