12.

Retirement Benefit Plans

We have defined benefit pension plans covering certain U.S. and Puerto Rico employees. The employees who are not participating in the defined benefit plans receive additional benefits under our defined contribution plans. Plan benefits are primarily based on years of credited service and the participant’s compensation. In addition to the U.S. and Puerto Rico defined benefit pension plans, we sponsor various foreign pension arrangements, including retirement and termination benefit plans required by local law or coordinated with government sponsored plans.

The components of net periodic pension expense for our U.S. and foreign defined benefit retirement plans are as follows (in millions):


	Three Months Ended March 31,
	2014			2013
Service cost	$	6.7		$	7.1
Interest cost		6.4			4.7
Expected return on plan assets		(10.4	)		(8.9	)
Amortization of prior service cost		(1.0	)		(1.0	)
Amortization of unrecognized actuarial loss		2.9			4.7

Net periodic pension expense	$	4.6		$	6.6

We contributed $2.0 million during the three month period ended March 31, 2014 to our U.S. and Puerto Rico defined benefit plans and do not expect to contribute additional funds to these plans during the remainder of 2014. We contributed $3.6 million to our foreign-based defined benefit plans in the three month period ended March 31, 2014 and expect to contribute $11.0 million to these foreign-based plans during the remainder of 2014.