Concentration	9 Months Ended
Sep. 30, 2013
Concentration
Concentration	Note 5. Concentration Tenant and Credit Concentration We define annualized rental income as the annualized contractual base rents from our tenants pursuant to our lease agreements with them as of the measurement date, plus straight line rent adjustments and estimated recurring expense reimbursements to be paid to us, and excluding lease value amortization. The U.S. Government, 10 state governments and the United Nations combined were responsible for approximately 93.9% and 93.7% of our annualized rental income, excluding properties classified as discontinued operations, as of September 30, 2013 and 2012, respectively. The U.S. Government is our largest tenant by annualized rental income and was responsible for approximately 71.2% and 70.2% of our annualized rental income, excluding properties classified as discontinued operations, as of September 30, 2013 and 2012, respectively. Geographic Concentration At September 30, 2013, our 81 properties, excluding properties classified as discontinued operations, were located in 31 states and the District of Columbia. Properties located in Maryland, California, the District of Columbia, Georgia, New York and Massachusetts were responsible for approximately 13.8%, 11.2%, 10.8%, 9.7%, 8.9% and 6.0% of our annualized rental income as of September 30, 2013, respectively.

Concentration

9 Months Ended

Sep. 30, 2013

Note 5. Concentration

Tenant and Credit Concentration

We define annualized rental income as the annualized contractual base rents from our tenants pursuant to our lease agreements with them as of the measurement date, plus straight line rent adjustments and estimated recurring expense reimbursements to be paid to us, and excluding lease value amortization. The U.S. Government, 10 state governments and the United Nations combined were responsible for approximately 93.9% and 93.7% of our annualized rental income, excluding properties classified as discontinued operations, as of September 30, 2013 and 2012, respectively. The U.S. Government is our largest tenant by annualized rental income and was responsible for approximately 71.2% and 70.2% of our annualized rental income, excluding properties classified as discontinued operations, as of September 30, 2013 and 2012, respectively.

Geographic Concentration

At September 30, 2013, our 81 properties, excluding properties classified as discontinued operations, were located in 31 states and the District of Columbia. Properties located in Maryland, California, the District of Columbia, Georgia, New York and Massachusetts were responsible for approximately 13.8%, 11.2%, 10.8%, 9.7%, 8.9% and 6.0% of our annualized rental income as of September 30, 2013, respectively.