The Company contributes to a multiemployer defined benefit pension plan under the terms of a collective-bargaining agreement that covers union-represented employees.

The Company has an unfunded postretirement healthcare plan which provides health insurance to certain employees and their spouses upon retirement. This plan has been frozen and no additional participants will be added to the plan in the future.


	2022		2021		2020
401(k) plan	$	3,580	$	3,196	$	2,403
Multiemployer and other defined benefit and pension plans	79		78		70
Postretirement healthcare plan	342		411		351
Total retirement plan expense	$	4,001	$	3,685	$	2,824

The Company's one multiemployer plan is underfunded and has a rehabilitation plan in place. The rehabilitation plan requires minimum contributions from the Company. Given the status of this plan, it is reasonably possible that future contributions to the plan will increase although the Company cannot reasonably estimate a possible range of increased contributions as of December 31, 2022.

The following table presents the changes in the accumulated postretirement benefit obligation related to the Company’s unfunded postretirement healthcare benefits at December 31 (in thousands):


	2022		2021
Projected benefit obligation at January 1	$	6,202	$	6,443

Interest cost	127		125

Plan amendments	—		162
Actuarial gain	(1,784)		(200)
Benefits paid, net of contributions	(316)		(328)
Projected benefit obligation at December 31	4,229		6,202
Fair value of plan assets	—		—
Under funded status	(4,229)		(6,202)
Unamortized prior service cost	352		412
Unrecognized actuarial (gain) loss	(278)		1,530
Net amount recognized	$	(4,155)	$	(4,260)


	2022		2021
Accrued postretirement benefit liability:
Current portion	$	353	$	358
Long term portion	3,876		5,844
Pre-tax accumulated other comprehensive loss – unamortized post-retirement healthcare costs	(74)		(1,942)
Net amount recognized	$	4,155	$	4,260

Components of net periodic postretirement benefit cost charged to expense for the years ended December 31 were as follows (in thousands):


	2022			2021			2020
Service cost	$	—		$	—		$	10
Interest cost	127			125			172
Amortization of unrecognized prior service cost	60			44			44
Loss amortization (2)	24			113			64
Net periodic benefit cost	$	211		$	282		$	290
Assumptions used to calculate the benefit obligation:
Discount rate	4.8		%	2.4		%	2.0		%
Annual rate of increase in the per capita cost of:
Medical costs before age 65 (1)	7.8		%	7.0		%	7.0		%
Medical costs after age 65 (1)	4.5		%	4.5		%	4.5		%
Prescription drug costs (1)	7.8		%	7.0		%	7.0		%

(1) For 2022, it was assumed that these rates would gradually decline to 4.0% by 2075. For 2021 and 2020, it was assumed that these rates would gradually decline to 3.8% by 2075.

(2) Actuarial losses are amortized utilizing the corridor approach. Differences between actual experience and the actuarial assumptions are reflected in (gain)/loss. If the total net (gain) or loss exceeds 10 percent of the greater of the accumulated postretirement benefit obligation or plan assets, this excess must be amortized over the average remaining service period of the active plan participants. If most of the plan participants are inactive, the amortization period is the expected future lifetime of inactive plan participants.