NOTE 10. RENTAL INCOME

During the year ended December 31, 2015, approximately 92% of rental income was related to residential apartments and condominium units with leases of one year or less. The majority of these leases expire in June, July and August. Approximately 8% was related to commercial properties, which have minimum future annual rental income on non‑cancellable operating leases at December 31, 2015 as follows:


	Commercial
	Property Leases
2016	$	2,826,000
2017		2,205,000
2018		1,922,000
2019		1,442,000
2020		869,000
Thereafter		796,000
	$	10,060,000

The aggregate minimum future rental income does not include contingent rentals that may be received under various leases in connection with common area charges and real estate taxes. Aggregate contingent rentals from continuing operations were approximately $683,000, $638,000 and $670,000 for the years ended December 31, 2015, 2014 and 2013 respectively. Staples and Trader Joes, tenants at Staples Plaza are approximately 31% of the total commercial rental income.

The following information is provided for commercial leases:


	Annual base				Percentage of
	rent for		Total square feet	Total number of	annual base rent for
Through December 31,	expiring leases		for expiring leases	leases expiring	expiring leases
2016	$	219,570	12,586	10	8	%
2017		596,631	17,646	9	21	%
2018		333,911	9,557	7	11	%
2019		747,914	25,500	10	26	%
2020		204,730	6,709	5	7	%
2021		647,765	31,274	3	22	%
2022		—	—	—	—	%
2023		157,442	4,771	1	5	%
2024		—	—	—	—	%
2025		—	—	—	—	%
Totals	$	2,907,963	108,043	45	100	%

Rents receivable are net of an allowance for doubtful accounts of approximately $373,000 and $366,000 at December 31, 2015 and 2014. Included in rents receivable at December 31, 2015 is approximately $135,000 resulting from recognizing rental income from non‑cancelable commercial leases with future rental increases on a straight‑line basis. The majority of this amount is for long‑term leases with Staples and Trader Joe’s at Staples Plaza in Framingham, Massachusetts.

Rents receivable at December 31, 2015 also includes approximately $119,000 representing the deferral of rental concession primarily related to the residential properties.

For the year ended December 31, 2015 rent at the commercial properties includes approximately $2,200, of amortization of deferred rents arising from the fair values assigned to in‑place leases upon the purchase of Cypress Street in Brookline, Massachusetts.