income tax liabilities tax liabilities related to unrecognized tax benefits as of 30 september 2018 were $ 233.6 . these tax liabilities were excluded from the contractual obligations table as it is impractical to determine a cash impact by year given that payments will vary according to changes in tax laws , tax rates , and our operating results . in addition , there are uncertainties in timing of the effective settlement of our uncertain tax positions with respective taxing authorities . however , the contractual obligations table above includes our accrued liability of approximately $ 184 for deemed repatriation tax that is payable over eight years related to the tax act . refer to note 22 , income taxes , to the consolidated financial statements for additional information . obligation for future contribution to an equity affiliate on 19 april 2015 , a joint venture between air products and acwa holding entered into a 20-year oxygen and nitrogen supply agreement to supply saudi aramco 2019s oil refinery and power plant being built in jazan , saudi arabia . air products owns 25% ( 25 % ) of the joint venture and guarantees the repayment of its share of an equity bridge loan . in total , we expect to invest approximately $ 100 in this joint venture . as of 30 september 2018 , we recorded a noncurrent liability of $ 94.4 for our obligation to make future equity contributions in 2020 based on our proportionate share of the advances received by the joint venture under the loan . expected investment in joint venture on 12 august 2018 , air products entered an agreement to form a gasification/power joint venture ( "jv" ) with saudi aramco and acwa in jazan , saudi arabia . air products will own at least 55% ( 55 % ) of the jv , with saudi aramco and acwa power owning the balance . the jv will purchase the gasification assets , power block , and the associated utilities from saudi aramco for approximately $ 8 billion . our expected investment has been excluded from the contractual obligations table above pending closing , which is currently expected in fiscal year 2020 . the jv will own and operate the facility under a 25-year contract for a fixed monthly fee . saudi aramco will supply feedstock to the jv , and the jv will produce power , hydrogen and other utilities for saudi aramco . pension benefits the company and certain of its subsidiaries sponsor defined benefit pension plans and defined contribution plans that cover a substantial portion of its worldwide employees . the principal defined benefit pension plans are the u.s . salaried pension plan and the u.k . pension plan . these plans were closed to new participants in 2005 , after which defined contribution plans were offered to new employees . the shift to defined contribution plans is expected to continue to reduce volatility of both plan expense and contributions . the fair market value of plan assets for our defined benefit pension plans as of the 30 september 2018 measurement date decreased to $ 4273.1 from $ 4409.2 at the end of fiscal year 2017 . the projected benefit obligation for these plans was $ 4583.3 and $ 5107.2 at the end of fiscal years 2018 and 2017 , respectively . the net unfunded liability decreased $ 387.8 from $ 698.0 to $ 310.2 , primarily due to higher discount rates and favorable asset experience . refer to note 16 , retirement benefits , to the consolidated financial statements for comprehensive and detailed disclosures on our postretirement benefits . pension expense .

1	2018	2017	2016
2	pension expense 2013 continuing operations	$ 91.8	$ 72.0	$ 55.8
3	settlements termination benefits and curtailments ( included above )	48.9	15.0	6.0
4	weighted average discount rate 2013 service cost	3.2% ( 3.2 % )	2.9% ( 2.9 % )	4.1% ( 4.1 % )
5	weighted average discount rate 2013 interest cost	2.9% ( 2.9 % )	2.5% ( 2.5 % )	3.4% ( 3.4 % )
6	weighted average expected rate of return on plan assets	6.9% ( 6.9 % )	7.4% ( 7.4 % )	7.5% ( 7.5 % )
7	weighted average expected rate of compensation increase	3.5% ( 3.5 % )	3.5% ( 3.5 % )	3.5% ( 3.5 % )

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Previous questions in this conversation: what was the total of operating expenses in 2018?
Previous answers: 91.8
Question: and what was it in 2017?
Answer: 72