19. Commitments and Contingencies: Operations The Company and its subsidiaries are primarily engaged in the operation of shopping centers that are either owned or held under long-term leases that expire at various dates through 2114. The Company and its subsidiaries, in turn, lease premises in these centers to tenants pursuant to lease agreements which provide for terms ranging generally from 5 to 25 years and for annual minimum rentals plus incremental rents based on operating expense levels and tenants' sales volumes. Annual minimum rentals plus incremental rents based on operating expense levels and percentage rents comprised 98% of total revenues from rental property for each of the three years ended December 31, 2015, 2014 and 2013. The future minimum revenues from rental property under the terms of all non-cancelable tenant leases, assuming no new or renegotiated leases are executed for such premises, for future years are as follows (in millions): 2016, $825.8; 2017, $741.4; 2018, $636.7; 2019, $541.5; 2020, $446.2 and thereafter; $1,955.2. Base rental revenues from rental property are recognized on a straight-line basis over the terms of the related leases. The difference between the amount of rental income contracted through leases and rental income recognized on a straight-line basis before allowances for the years ended December 31, 2015, 2014 and 2013 was $14.8 million, $8.4 million and $4.8 million, respectively. Minimum rental payments to be made by the Company under the terms of all non-cancelable operating leases pertaining to the Companys shopping center portfolio for future years are as follows (in millions): 2016, $12.7; 2017, $12.3; 2018, $12.0; 2019, $11.2; 2020, $10.7 and thereafter, $193.6. Guarantees On a select basis, the Company had provided guarantees on interest bearing debt held within real estate joint ventures. The Company had the following outstanding guarantees as of December 31, 2015 (amounts in millions): Name of Joint Venture Amount of Guarantee Interest rate Maturity, with ext