ension and Non-pension Postretirement Benefits

We have pension plans covering the majority of our employees. Benefits generally are based on compensation and service for salaried employees and job grade and length of service for hourly employees. In addition, we have an unfunded supplemental employee retirement plan (SERP) that covers certain salaried U.S.-based employees of Libbey hired before January 1, 2006. The U.S. pension plans cover the salaried U.S.-based employees of Libbey hired before January 1, 2006 and most hourly U.S.-based employees (excluding employees hired at Shreveport after 2008 and at Toledo after September 30, 2010). Effective January 1, 2013, we ceased annual company contribution credits to the cash balance accounts in our Libbey U.S. Salaried Pension Plan and SERP. The non-U.S. pension plans cover the employees of our wholly owned subsidiary in Mexico. The plan in Mexico is unfunded.

In the fourth quarter of 2015, we executed an agreement with Pensioenfonds voor de Grafische Bedrijven (“PGB”), an industry wide pension fund, and unwound direct ownership of our defined benefit pension plan in the Netherlands. In accordance with this agreement, we transferred all assets of the plan to PGB, which now assumes the related liabilities and administrative responsibilities of the plan. In 2016, Libbey Holland continues to make cash contributions to PGB as participating employees earn pension benefits. These related costs are expensed as incurred and are excluded from 2016 pension expense below.

The components of our net pension expense, including the SERP, are as follows:



Three months ended March 31,	U.S. Plans						Non-U.S. Plans						Total
(dollars in thousands)	2016			2015			2016			2015			2016			2015
Service cost	$	996		$	1,161		$	317		$	748		$	1,313		$	1,909
Interest cost	3,777			3,709			672			1,103			4,449			4,812
Expected return on plan assets	(5,755		)	(5,662		)	—			(598		)	(5,755		)	(6,260		)
Amortization of unrecognized:
Prior service cost	66			104			(54		)	(64		)	12			40
Actuarial loss	1,120			1,886			202			406			1,322			2,292
Pension expense	$	204		$	1,198		$	1,137		$	1,595		$	1,341		$	2,793

We have contributed $1.5 million of cash into our pension plans for the three months ended March 31, 2016. Pension contributions for the remainder of 2016 are estimated to be $1.0 million.

We provide certain retiree health care and life insurance benefits covering our U.S. and Canadian salaried employees hired before January 1, 2004 and a majority of our union hourly employees (excluding employees hired at Shreveport after 2008 and at Toledo after September 30, 2010). Employees are generally eligible for benefits upon retirement and completion of a specified number of years of creditable service. Benefits for most hourly retirees are determined by collective bargaining. The U.S. non-pension postretirement plans cover the hourly and salaried U.S.-based employees of Libbey (excluding those mentioned above). The non-U.S. non-pension postretirement plans cover the retirees and active employees of Libbey who are located in Canada. The postretirement benefit plans are unfunded.

The provision for our non-pension postretirement benefit expense consists of the following:



Three months ended March 31,	U.S. Plans				Non-U.S. Plans					Total
(dollars in thousands)	2016		2015		2016			2015		2016		2015
Service cost	$	199	$	282	$	—		$	—	$	199	$	282
Interest cost	652		660		12			19		664		679
Amortization of unrecognized:
Prior service cost	35		35		—			—		35		35
Actuarial loss / (gain)	20		196		(11		)	—		9		196
Non-pension postretirement benefit expense	$	906	$	1,173	$	1		$	19	$	907	$	1,192

Our 2016 estimate of non-pension cash payments is $5.0 million, and we have paid $0.8 million for the three months ended March 31, 2016.