loan activity . from time to time , we make loans to owners of hotels that we operate or franchise . loan collections , net of loan advances , amounted to $ 35 million in 2018 , compared to net collections of $ 94 million in 2017 . at year-end 2018 , we had $ 131 million of senior , mezzanine , and other loans outstanding , compared to $ 149 million outstanding at year-end 2017 . equity method investments . cash outflows of $ 72 million in 2018 , $ 62 million in 2017 , and $ 13 million in 2016 for equity method investments primarily reflect our investments in several joint ventures . financing activities cash flows debt . debt increased by $ 1109 million in 2018 , to $ 9347 million at year-end 2018 from $ 8238 million at year-end 2017 , primarily due to the issuance of our series x , y , z , and aa notes , partially offset by the maturity of our series s notes ( $ 330 million ) and lower outstanding commercial paper ( $ 126 million ) . see footnote 10 . long-term debt for additional information on the debt issuances . our financial objectives include diversifying our financing sources , optimizing the mix and maturity of our long-term debt , and reducing our working capital . at year-end 2018 , our long-term debt had a weighted average interest rate of 3.3 percent and a weighted average maturity of approximately 4.8 years . the ratio of our fixed-rate long-term debt to our total long-term debt was 0.7 to 1.0 at year-end 2018 . see the 201ccash requirements and our credit facility , 201d caption in this 201cliquidity and capital resources 201d section for more information on our credit facility . share repurchases . we purchased 21.5 million shares of our common stock in 2018 at an average price of $ 130.67 per share , 29.2 million shares in 2017 at an average price of $ 103.66 per share , and 8.0 million shares in 2016 at an average price of $ 71.55 per share . at year-end 2018 , 10.7 million shares remained available for repurchase under board approved authorizations , and on february 15 , 2019 , our board of directors further increased our common stock repurchase authorization by 25 million shares . for additional information , see 201cfourth quarter 2018 issuer purchases of equity securities 201d in part ii , item 5 . dividends . our board of directors declared the following quarterly cash dividends in 2018 : ( 1 ) $ 0.33 per share declared on february 9 , 2018 and paid march 30 , 2018 to shareholders of record on february 23 , 2018 , ( 2 ) $ 0.41 per share declared on may 4 , 2018 and paid june 29 , 2018 to shareholders of record on may 18 , 2018 , ( 3 ) $ 0.41 per share declared on august 9 , 2018 and paid september 28 , 2018 to shareholders of record on august 23 , 2018 , and ( 4 ) $ 0.41 per share declared on november 8 , 2018 and paid december 31 , 2018 to shareholders of record on november 21 , 2018 . our board of directors declared a cash dividend of $ 0.41 per share on february 15 , 2019 , payable on march 29 , 2019 to shareholders of record on march 1 , 2019 . contractual obligations and off-balance sheet arrangements contractual obligations the following table summarizes our contractual obligations at year-end 2018: .
of the total contractual obligations and off-balance sheet arrangements contractual obligations what percentage is due to operating leases where we are the primary obligor?
( 1 ) includes principal as well as interest payments . the preceding table does not reflect transition tax payments totaling $ 507 million as a result of the 2017 tax act . in addition , the table does not reflect unrecognized tax benefits at year-end 2018 of $ 559 million . in addition to the purchase obligations noted in the preceding table , in the normal course of business we enter into purchase commitments to manage the daily operating needs of the hotels that we manage . since we are reimbursed from the cash flows of the hotels , these obligations have minimal impact on our net income and cash flow. .