Read the following texts and table with financial data from an S&P 500 earnings report carefully.Based on the question-answer history (if provided), answer the last question. The answer may require mathematical calculation based on the data provided.


financial statement impact we believe that our accruals for sales returns , rebates , and discounts are reasonable and appropriate based on current facts and circumstances . our global rebate and discount liabilities are included in sales rebates and discounts on our consolidated balance sheet . our global sales return liability is included in other current liabilities and other noncurrent liabilities on our consolidated balance sheet . as of december 31 , 2018 , a 5 percent change in our global sales return , rebate , and discount liability would have led to an approximate $ 275 million effect on our income before income taxes . the portion of our global sales return , rebate , and discount liability resulting from sales of our products in the u.s . was approximately 90 percent as of december 31 , 2018 and december 31 , 2017 . the following represents a roll-forward of our most significant u.s . pharmaceutical sales return , rebate , and discount liability balances , including managed care , medicare , and medicaid: . <table class='wikitable'><tr><td>1</td><td>( dollars in millions )</td><td>2018</td><td>2017</td></tr><tr><td>2</td><td>sales return rebate and discount liabilities beginning of year</td><td>$ 4172.0</td><td>$ 3601.8</td></tr><tr><td>3</td><td>reduction of net sales due to sales returns discounts and rebates ( 1 )</td><td>12529.6</td><td>10603.4</td></tr><tr><td>4</td><td>cash payments of discounts and rebates</td><td>-12023.4 ( 12023.4 )</td><td>-10033.2 ( 10033.2 )</td></tr><tr><td>5</td><td>sales return rebate and discount liabilities end of year</td><td>$ 4678.2</td><td>$ 4172.0</td></tr></table> ( 1 ) adjustments of the estimates for these returns , rebates , and discounts to actual results were approximately 1 percent of consolidated net sales for each of the years presented . product litigation liabilities and other contingencies background and uncertainties product litigation liabilities and other contingencies are , by their nature , uncertain and based upon complex judgments and probabilities . the factors we consider in developing our product litigation liability reserves and other contingent liability amounts include the merits and jurisdiction of the litigation , the nature and the number of other similar current and past matters , the nature of the product and the current assessment of the science subject to the litigation , and the likelihood of settlement and current state of settlement discussions , if any . in addition , we accrue for certain product liability claims incurred , but not filed , to the extent we can formulate a reasonable estimate of their costs based primarily on historical claims experience and data regarding product usage . we accrue legal defense costs expected to be incurred in connection with significant product liability contingencies when both probable and reasonably estimable . we also consider the insurance coverage we have to diminish the exposure for periods covered by insurance . in assessing our insurance coverage , we consider the policy coverage limits and exclusions , the potential for denial of coverage by the insurance company , the financial condition of the insurers , and the possibility of and length of time for collection . due to a very restrictive market for product liability insurance , we are self-insured for product liability losses for all our currently marketed products . in addition to insurance coverage , we also consider any third-party indemnification to which we are entitled or under which we are obligated . with respect to our third-party indemnification rights , these considerations include the nature of the indemnification , the financial condition of the indemnifying party , and the possibility of and length of time for collection . the litigation accruals and environmental liabilities and the related estimated insurance recoverables have been reflected on a gross basis as liabilities and assets , respectively , on our consolidated balance sheets . impairment of indefinite-lived and long-lived assets background and uncertainties we review the carrying value of long-lived assets ( both intangible and tangible ) for potential impairment on a periodic basis and whenever events or changes in circumstances indicate the carrying value of an asset ( or asset group ) may not be recoverable . we identify impairment by comparing the projected undiscounted cash flows to be generated by the asset ( or asset group ) to its carrying value . if an impairment is identified , a loss is recorded equal to the excess of the asset 2019s net book value over its fair value , and the cost basis is adjusted . goodwill and indefinite-lived intangible assets are reviewed for impairment at least annually and when certain impairment indicators are present . when required , a comparison of fair value to the carrying amount of assets is performed to determine the amount of any impairment. .
Question: what was the reduction of net sales due to sales returns discounts and rebates in 2018?
Answer: 12529.6
Question: and what was it in 2017?

10603.4