Table of Contents Pension expense is affected by the accounting policy used to determine the value of plan assets at the measurement date. The Company applies the expected return on plan assets using fair market value as of the annual measurement date. The fair market value method results in greater volatility to pension expense than the calculated value method. The amounts recognized in the Consolidated Balance Sheets reflect the fair value of the Company's long-term pension liabilities at the plan measurement date and the fair value of plan assets as of the balance sheet date. Net periodic benefit cost related to all of the Company's defined benefit pension plans recognized in the Company's Consolidated Statements of Operations for the years ended December 31  2018  2017  and 2016 included the following components: Benefit cost for the U.S. Qualified Plan does not include service cost since the plan is frozen. Year Ended December 31  2018 2017 2016 (In thousands) Service cost $ 1 395 $ 1 288 $ 1 218 Interest cost 20 933 22 723 30 129 Expected return on assets (34 267 ) (34 056 ) (36 406 ) Amortization of actuarial loss 10 744 11 154 12 840 Net periodic benefit (credit) cost $ (1 195 ) $ 1 109 $ 7 781 Year Ending December 31  Expected Benefit Payments (In thousands) 2019 $ 43 607 2020 44 102 2021 44 373 2022 44 595 2023 44 663 2024-2028 220 848 Over the next ten years  the following benefit payments are expected to be required to be made from the Company's U.S. and U.K. defined benefit pension plans: The Company reviews its employee demographic assumptions annually and updates the assumptions as necessary. The Company updates the mortality assumptions for the U.S. plans to incorporate the current mortality tables issued by the Society of Actuaries  adjusted to reflect the Company's specific experience and future expectations. This resulted in a $1 300 000 decrease in the projected benefit obligation for the U.S. plans for the year ended December 31  2018. Certain assumptions used in computing the benefit obligations and net periodic benefit cost for the U.S. and U.K. defined benefit pension plans were as follows: The discount rate assumptions reflect the rates at which the Company believes the benefit obligations could be effectively settled. The discount rates were determined based on the yield for a portfolio of investment grade corporate bonds with maturity dates matched to the estimated future payments of the plans' benefit obligations. 88 U.K. Defined Benefit Plans: 2018 2017 Discount rate used to compute benefit obligations 2.77 % 2.61 % Discount rate used to compute periodic benefit cost 2.61% 2.65% Expected long-term rates of return on plans' assets 3.98 % 4.23 % U.S. Qualified Plan: 2018 2017 Discount rate used to compute benefit obligations 4.30 % 3.63 % Discount rate used to compute periodic benefit cost 3.63% 4.15% Expected long-term rates of return on plans' assets 6.20 % 6.30 %