Only 42 of the Fortune 100 companies now offer defined benefit pension plans to new hires, down from 45 in 2009.

Analysts at Towers Watson & Company, New York (NYSE:TW), have published those figures in a report based on retirement benefit plan information from 100 giant U.S. companies.

The number of Fortune 100 employers that offer new hires only defined contribution retirement plans, such as 401(k) plans, has increased to 58, from 55, Towers Watson says.

The number of Fortune 100 employers offering “hybrid” plans – which resemble defined contribution plans in some ways but have the backing of the Pension Benefit Guaranty Corp. – held steady at 25.

The number offering traditional defined benefit pension plans fell to 17, from 20.

Two years ago, a Towers Watson predecessor firm found a new pension law had slowed changes in Fortune 100 retirement benefits.