table of contents the following table presents certain payments due by the company under contractual obligations with minimum firm commitments as of september 28 , 2013 and excludes amounts already recorded on the consolidated balance sheet , except for long-term debt ( in millions ) : lease commitments the company 2019s major facility leases are typically for terms not exceeding 10 years and generally provide renewal options for terms not exceeding five additional years . leases for retail space are for terms ranging from five to 20 years , the majority of which are for 10 years , and often contain multi-year renewal options . as of september 28 , 2013 , the company 2019s total future minimum lease payments under noncancelable operating leases were $ 4.7 billion , of which $ 3.5 billion related to leases for retail space . purchase commitments with outsourcing partners and component suppliers the company utilizes several outsourcing partners to manufacture sub-assemblies for the company 2019s products and to perform final assembly and testing of finished products . these outsourcing partners acquire components and build product based on demand information supplied by the company , which typically covers periods up to 150 days . the company also obtains individual components for its products from a wide variety of individual suppliers . consistent with industry practice , the company acquires components through a combination of purchase orders , supplier contracts , and open orders based on projected demand information . where appropriate , the purchases are applied to inventory component prepayments that are outstanding with the respective supplier . as of september 28 , 2013 , the company had outstanding off-balance sheet third- party manufacturing commitments and component purchase commitments of $ 18.6 billion . other obligations in addition to the off-balance sheet commitments mentioned above , the company had outstanding obligations of $ 1.3 billion as of september 28 , 2013 , that consisted mainly of commitments to acquire capital assets , including product tooling and manufacturing process equipment , and commitments related to advertising , research and development , internet and telecommunications services and other obligations . the company 2019s other non-current liabilities in the consolidated balance sheets consist primarily of deferred tax liabilities , gross unrecognized tax benefits and the related gross interest and penalties . as of september 28 , 2013 , the company had non-current deferred tax liabilities of $ 16.5 billion . additionally , as of september 28 , 2013 , the company had gross unrecognized tax benefits of $ 2.7 billion and an additional $ 590 million for gross interest and penalties classified as non-current liabilities . at this time , the company is unable to make a reasonably reliable estimate of the timing of payments in individual years in connection with these tax liabilities ; therefore , such amounts are not included in the above contractual obligation table . indemnification the company generally does not indemnify end-users of its operating system and application software against legal claims that the software infringes third-party intellectual property rights . other agreements entered into by payments due in than 1 payments due in payments due in payments due in than 5 years total .

payments due in less than1 year: long-term debt: 0
operating leases: 610
purchase obligations: 18616
other obligations: 1081
total: 20307
payments due in 1-3 years: long-term debt: 2500
operating leases: 1200
purchase obligations: 0
other obligations: 248
total: 3948
payments due in 4-5 years: long-term debt: 6000
operating leases: 1056
purchase obligations: 0
other obligations: 16
total: 7072
payments due in more than5 years: long-term debt: 8500
operating leases: 1855
purchase obligations: 0
other obligations: 3
total: 10358
total: long-term debt: 17000
operating leases: 4721
purchase obligations: 18616
other obligations: 1348
total: 41685

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Questions:
as of september 28, 2013, what was the total of the non-current deferred tax liabilities the company had?
and what was the balance of gross unrecognized tax benefits?
what was, then, the difference between them, in billions?
and as of that same date, what was the total of the purchase obligations?
and what percentage did this total represent in relation to the total of certain payments due by the company under contractual obligations?

Answers:
16.5
2.7
13.8
18616
44.7%