The following table summarizes NNN’s Property Portfolio as of December 31, 2013 (in thousands): As of December 31, 2013, NNN has agreed to fund construction commitments on leased Properties, estimated to be completed  within 12 months, as outlined in the table below (dollars in thousands): As of December 31, 2013, NNN did not have any tenant that accounted for ten percent or more of its rental income. Leases The following is a summary of the general structure of NNN’s Property leases, although the specific terms of each lease can  vary. Generally, the Property leases provide for initial terms of 15 to 20 years. As of December 31, 2013, the weighted average  remaining lease term of the Property Portfolio was approximately 12 years. The Properties are generally leased under net  leases, pursuant to which the tenant typically bears responsibility for substantially all property costs and expenses associated  with ongoing maintenance and operation, including utilities, property taxes and insurance. NNN's Property leases provide for  annual base rental payments (payable in monthly installments) ranging from $1,000 to $2,607,000 (average of $211,000), and  generally provide for limited increases in rent as a result of fixed increases, increases in the Consumer Price Index (“CPI”),  and/or, to a lesser extent, increases in the tenant’s sales volume. Generally, the Property leases provide the tenant with one or more multi-year renewal options subject to generally the same  terms and conditions provided under the initial lease term. Some of the leases also provide that in the event NNN wishes to sell  the Property subject to that lease, NNN first must offer the lessee the right to purchase the Property on the same terms and  conditions as any offer which NNN intends to accept for the sale of the Property. The following table summarizes the lease expirations, assuming none of the tenants exercise renewal options, of NNN’s  Property Portfolio for each of the next 10 years and then thereafter in the aggregate as of December 31, 2013: (1) $^{}$Based on annualized base rent for all leases in place as of December 31, 2013. (2)  Approximate square feet. % of Annual Base Rent (1) # of Properties Gross Leasable Area (2) % of Annual Base Rent (1) # of Properties Gross Leasable Area (2) 2014 1.4% 32 434,000 2020 3.1% 97 916,000 2015 1.6% 32 482,000 2021 4.6% 99 918,000 2016 1.7% 32 567,000 2022 6.9% 92 1,150,000 2017 3.5% 46 1,009,000 2023 3.3% 54 962,000 2018 8.3% 186 1,957,000 Thereafter 62.1% 1,092 10,472,000 2019 3.5% 57 1,005,000 Number of properties 48 Total commitment (1) $ 145,818 Amount funded 99,024 Remaining commitment 46,794 $^{(1)}$  Includes land, construction costs and tenant improvements. (1) $^{}$Approximate square feet. (2)  Costs vary depending upon size and local demographic factors. Size (1) Acquisition Cost (2) High Low Average High Low Average Land 2,223 5 100 $ 8,882 $ 5 $ 920 Building 142 1 11 29,373 19 1,674  4