CONCENTRATIONS

Tenant Revenue Concentrations—Rental revenue, excluding tenant reimbursements of certain costs, from the U.S. General Services Administration and other government agencies (collectively, "Governmental Tenants"), which primarily occupy properties located in Washington, D.C., accounted for approximately 21.4%, 19.9% and 22.7% of our rental and other property income for the years ended December 31, 2017, 2016 and 2015, respectively. At December 31, 2017 and 2016, $5,130,000 and $8,339,000, respectively, was due from Governmental Tenants (Note 17).

Geographical Concentrations of Investments in Real Estate—As of December 31, 2017, 2016 and 2015, we owned 15, 20 and 20 office properties, respectively; zero, five and five multifamily properties, respectively; one, one and three hotel properties, respectively; two, three and three parking garages, respectively; and two development sites, one of which is being used as a parking lot. As of December 31, 2017, 2016 and 2015, these properties were located in two, four and four states, respectively, and Washington, D.C.

Our revenue concentrations from properties are as follows:



	Year Ended December 31,
	2017		2016		2015
California	63.2	%	63.4	%	62.2	%
Washington, D.C.	25.1		21.3		24.2
Texas	6.9		8.2		7.8
North Carolina	3.1		5.2		4.6
New York	1.7		1.9		1.2
	100.0	%	100.0	%	100.0	%

Our real estate investments concentrations from properties are as follows:



	December 31,
	2017		2016
California	66.4	%	50.8	%
Washington, D.C.	31.2		32.3
Texas	2.4		7.7
North Carolina	—		5.5
New York	—		3.7
	100.0	%	100.0	%