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: .

2018: sales return rebate and discount liabilities beginning of year: 4172
reduction of net sales due to sales returns discounts and rebates ( 1 ): 12529.6
cash payments of discounts and rebates: -12023.4
sales return rebate and discount liabilities end of year: 4678.2
2017: sales return rebate and discount liabilities beginning of year: 3601.8
reduction of net sales due to sales returns discounts and rebates ( 1 ): 10603.4
cash payments of discounts and rebates: -10033.2
sales return rebate and discount liabilities end of year: 4172

( 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. .

Questions:
what was the reduction of net sales due to sales returns discounts and rebates in 2018?
and what was it in 2017?
what was, then, the change over the year?
what was the reduction of net sales due to sales returns discounts and rebates in 2017?
how much, then, does that change represent in relation to this 2017 reduction, in percentage?

Answers:
12529.6
10603.4
1926.2
10603.4
18%