Retirement plan costs fell for both small and large plans alike, according to the 13th edition of the 401(k) Averages Book.

In 2012, small retirement plans with 50 participants and $2.5 million in assets had an average total plan cost of 1.46%, down from 1.47% in 2011. Large retirement plans with 1,000 participants and $50 million in assets had a steeper decline, with the average plan cost dropping from 1.08% to 1.03%.

Investment expenses also fell. The average investment expense for small plans went from 1.38% to 1.37%. For large plans, it dropped from 1.05% to 1.00%. 

“401k fees have been trending down over the years but the Department of Labor’s fee disclosure regulations helped bring a great deal of attention to 401k plan fees,” Joseph Valletta, co-author of the book, said in statement. “More plan sponsors and their advisors recognize the importance of plan fees and the wide range of fees in the marketplace.”

The study also looked at the average cost of target date funds for the first time.  The average target date fund expense for a large plan is .98%.  For a small plan, it’s 1.37%, according to the report.

“Since target date fund usage continues to grow in 401k plans we thought it was important to calculate the average cost of target date funds available within 401k offerings,” report co-author David Huntley said in a statement.

The 401(k) Averages Book is published by Pension Data Source, a financial publishing company.