NOTE 10. RENTAL INCOME

During the year ended December 31, 2016, approximately 93% 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 7% was related to commercial properties, which have minimum future annual rental income on non‑cancellable operating leases at December 31, 2016 as follows:


	Commercial
	Property Leases
2017	$	2,692,000
2018		2,467,000
2019		1,988,000
2020		1,525,000
2021		1,083,000
Thereafter		614,000
	$	10,369,000

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 $616,000, $683,000 and $638,000 for the years ended December 31, 2016, 2015 and 2014 respectively. Staples and Trader Joes, tenants at Staples Plaza are approximately 30% 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
2017	$	298,019	13,430	10	10	%
2018		333,911	9,557	7	11	%
2019		699,908	24,688	12	24	%
2020		191,771	4,739	6	6	%
2021		829,156	40,323	6	29	%
2022		370,044	8,677	3	12	%
2023		157,443	4,771	1	5	%
2024		94,184	1,858	1	3	%
2025		—	—	—	—	%
2026		—	—	—	—	%
Totals	$	2,974,436	108,043	46	100	%

Rents receivable are net of an allowance for doubtful accounts of approximately $523,000 and $373,000 at December 31, 2016 and 2015. Included in rents receivable at December 31, 2016 is approximately $113,000 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, 2016 also includes approximately $138,000 representing the deferral of rental concession primarily related to the residential properties.

For the year ended December 31, 2016 rent at the commercial properties includes approximately $2,000, of amortization of deferred rents arising from the fair values assigned to in‑place leases upon the purchase of Cypress Street in Brookline, Massachusetts.