interest expense , net was $ 26.4 million , $ 14.6 million , and $ 5.3 million for the years ended december 31 , 2016 , 2015 and 2014 , respectively . interest expense includes the amortization of deferred financing costs , bank fees , capital and built-to-suit lease interest and interest expense under the credit and other long term debt facilities . amortization of deferred financing costs was $ 1.2 million , $ 0.8 million , and $ 0.6 million for the years ended december 31 , 2016 , 2015 and 2014 , respectively . the company monitors the financial health and stability of its lenders under the credit and other long term debt facilities , however during any period of significant instability in the credit markets lenders could be negatively impacted in their ability to perform under these facilities . 6 . commitments and contingencies obligations under operating leases the company leases warehouse space , office facilities , space for its brand and factory house stores and certain equipment under non-cancelable operating leases . the leases expire at various dates through 2033 , excluding extensions at the company 2019s option , and include provisions for rental adjustments . the table below includes executed lease agreements for brand and factory house stores that the company did not yet occupy as of december 31 , 2016 and does not include contingent rent the company may incur at its stores based on future sales above a specified minimum or payments made for maintenance , insurance and real estate taxes . the following is a schedule of future minimum lease payments for non-cancelable real property operating leases as of december 31 , 2016 as well as significant operating lease agreements entered into during the period after december 31 , 2016 through the date of this report : ( in thousands ) .

$ 114857: 2018: 127504
2019: 136040
2020: 133092
2021: 122753
2022 and thereafter: 788180
total future minimum lease payments: 1422426

included in selling , general and administrative expense was rent expense of $ 109.0 million , $ 83.0 million and $ 59.0 million for the years ended december 31 , 2016 , 2015 and 2014 , respectively , under non-cancelable operating lease agreements . included in these amounts was contingent rent expense of $ 13.0 million , $ 11.0 million and $ 11.0 million for the years ended december 31 , 2016 , 2015 and 2014 , respectively . sports marketing and other commitments within the normal course of business , the company enters into contractual commitments in order to promote the company 2019s brand and products . these commitments include sponsorship agreements with teams and athletes on the collegiate and professional levels , official supplier agreements , athletic event sponsorships and other marketing commitments . the following is a schedule of the company 2019s future minimum payments under its sponsorship and other marketing agreements as of december 31 .

Questions:
what was the rent expense in 2016?
and what was it in 2015?
what was, then, the change over the year?
what was the rent expense in 2015?
and how much does that change represent in relation to this 2015 amount, in percentage?

Answers:
109.0
83.0
26
83.0
31.3%