notes receivable in 2014 , we entered into a $ 3.0 million promissory note with a privately held company which was recorded at cost . the interest rate on the promissory note is 8.0% ( 8.0 % ) per annum and is payable quarterly . all unpaid principal and accrued interest on the promissory note is due and payable on the earlier of august 26 , 2017 , or upon default . 5 . commitments and contingencies operating leases we lease various operating spaces in north america , europe , asia and australia under non-cancelable operating lease arrangements that expire on various dates through 2024 . these arrangements require us to pay certain operating expenses , such as taxes , repairs , and insurance and contain renewal and escalation clauses . we recognize rent expense under these arrangements on a straight-line basis over the term of the lease . as of december 31 , 2015 , the aggregate future minimum payments under non-cancelable operating leases consist of the following ( in thousands ) : years ending december 31 .
what is the growth rate in the rent expense for operating leases in 2015?
rent expense for all operating leases amounted to $ 6.7 million , $ 3.3 million and $ 3.6 million for the years ended december 31 , 2015 , 2014 and 2013 , respectively . financing obligation 2014build-to-suit lease in august 2012 , we executed a lease for a building then under construction in santa clara , california to serve as our headquarters . the lease term is 120 months and commenced in august 2013 . based on the terms of the lease agreement and due to our involvement in certain aspects of the construction such as our financial involvement in structural elements of asset construction , making decisions related to tenant improvement costs and purchasing insurance not reimbursable by the buyer-lessor ( the landlord ) , we were deemed the owner of the building ( for accounting purposes only ) during the construction period . we continue to maintain involvement in the property post construction completion and lack transferability of the risks and rewards of ownership , due to our required maintenance of a $ 4.0 million letter of credit , in addition to our ability and option to sublease our portion of the leased building for fees substantially higher than our base rate . due to our continued involvement in the property and lack of transferability of related risks and rewards of ownership to the landlord post construction , we account for the building and related improvements as a lease financing obligation . accordingly , as of december 31 , 2015 and 2014 , we have recorded assets of $ 53.4 million , representing the total costs of the building and improvements incurred , including the costs paid by the lessor ( the legal owner of the building ) and additional improvement costs paid by us , and a corresponding financing obligation of $ 42.5 million and $ 43.6 million , respectively . as of december 31 , 2015 , $ 1.3 million and $ 41.2 million were recorded as short-term and long-term financing obligations , respectively . land lease expense under our lease financing obligation included in rent expense above , amounted to $ 1.3 million and $ 1.2 million for the years ended december 31 , 2015 and 2014 , respectively . there was no land lease expense for the year ended december 31 , 2013. .