13 . rentals and leases the company leases sales and administrative office facilities , distribution centers , research and manufacturing facilities , as well as vehicles and other equipment under operating leases . total rental expense under the company 2019s operating leases was $ 239 million in 2017 and $ 221 million in both 2016 and 2015 . as of december 31 , 2017 , identifiable future minimum payments with non-cancelable terms in excess of one year were : ( millions ) .

$ 131: 2019: 115
2020: 96
2021: 86
2022: 74
thereafter: 115
total: 617

the company enters into operating leases for vehicles whose non-cancelable terms are one year or less in duration with month-to-month renewal options . these leases have been excluded from the table above . the company estimates payments under such leases will approximate $ 62 million in 2018 . these vehicle leases have guaranteed residual values that have historically been satisfied by the proceeds on the sale of the vehicles . 14 . research and development expenditures research expenditures that relate to the development of new products and processes , including significant improvements and refinements to existing products , are expensed as incurred . such costs were $ 201 million in 2017 , $ 189 million in 2016 and $ 191 million in 2015 . the company did not participate in any material customer sponsored research during 2017 , 2016 or 2015 . 15 . commitments and contingencies the company is subject to various claims and contingencies related to , among other things , workers 2019 compensation , general liability ( including product liability ) , automobile claims , health care claims , environmental matters and lawsuits . the company is also subject to various claims and contingencies related to income taxes , which are discussed in note 12 . the company also has contractual obligations including lease commitments , which are discussed in note 13 . the company records liabilities where a contingent loss is probable and can be reasonably estimated . if the reasonable estimate of a probable loss is a range , the company records the most probable estimate of the loss or the minimum amount when no amount within the range is a better estimate than any other amount . the company discloses a contingent liability even if the liability is not probable or the amount is not estimable , or both , if there is a reasonable possibility that a material loss may have been incurred . insurance globally , the company has insurance policies with varying deductibility levels for property and casualty losses . the company is insured for losses in excess of these deductibles , subject to policy terms and conditions and has recorded both a liability and an offsetting receivable for amounts in excess of these deductibles . the company is self-insured for health care claims for eligible participating employees , subject to certain deductibles and limitations . the company determines its liabilities for claims on an actuarial basis . litigation and environmental matters the company and certain subsidiaries are party to various lawsuits , claims and environmental actions that have arisen in the ordinary course of business . these include from time to time antitrust , commercial , patent infringement , product liability and wage hour lawsuits , as well as possible obligations to investigate and mitigate the effects on the environment of the disposal or release of certain chemical substances at various sites , such as superfund sites and other operating or closed facilities . the company has established accruals for certain lawsuits , claims and environmental matters . the company currently believes that there is not a reasonably possible risk of material loss in excess of the amounts accrued related to these legal matters . because litigation is inherently uncertain , and unfavorable rulings or developments could occur , there can be no certainty that the company may not ultimately incur charges in excess of recorded liabilities . a future adverse ruling , settlement or unfavorable development could result in future charges that could have a material adverse effect on the company 2019s results of operations or cash flows in the period in which they are recorded . the company currently believes that such future charges related to suits and legal claims , if any , would not have a material adverse effect on the company 2019s consolidated financial position . environmental matters the company is currently participating in environmental assessments and remediation at approximately 45 locations , the majority of which are in the u.s. , and environmental liabilities have been accrued reflecting management 2019s best estimate of future costs . potential insurance reimbursements are not anticipated in the company 2019s accruals for environmental liabilities. .

Questions:
what were the r&d costs in 2016?
what were the r&d costs in 2015?
what is the net difference?
what were the r&d costs in 2015?
what was the percent change?

Answers:
189
191
-2
191
-1.0%