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Our overall expected long-term rate of return on assets for the pension trust fund is 7.5% as of January 1, 2020, which is both a pre-tax and after-tax rate as pension funds are generally not subject to income tax. Our overall expected long-term rate of return on assets for the other post- retirement benefits trust, on an after-tax basis, is 6.00% as of January 1, 2020. The expected returns on investments in the pension trust and the other post-retirement benefits trust are based upon the target asset allocations for the two trusts. 

Our accrued post-retirement benefit liability and the service and interest components of the related net periodic benefit costs are calculated using an actuarial assumption regarding health care cost inflation. For measurement purposes, a 5.75%, 6.75%, 4.5% and 7.0% annual rate of increase in the per capita cost of covered health care benefits was assumed for 2020 for pre-65 medical, pre-65 drug, post-65 medical and post-65 drug, respectively. The health care cost trend rates are assumed to decline steadily to an ultimate rate of 4.5% by 2025 for pre-65 medical and by 2026 for pre-65 and post-65 drug. Post-65 medical trend is assumed to be 4.5% for all years into the future. Assumed health care cost trend rates have a significant effect on the amounts reported for the health care plan. 

The estimated rate of compensation increase used in our retirement plans is 4.5% and is based on recent trends for all non-union employees and the amounts we are contractually obligated for union employees. 

The following table reflects the sensitivities that a change in certain actuarial assumptions would have had on the December 31, 2019 reported pension liability and our 2019 reported pension expense (in thousands): 

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The following chart reflects the sensitivities that a change in certain actuarial assumptions would have had on the December 31, 2019 other post-retirement benefit obligation and our 2019 reported other post-retirement benefit expense (in thousands): 

<img src='content_image/1053839.jpg'>

