Property:

Property at December 31, 2014 and 2013 consists of the following:



	2014			2013
Land	$	2,242,291		$	1,707,005
Buildings and improvements	9,479,337			6,555,212
Tenant improvements	600,436			537,754
Equipment and furnishings	152,554			152,198
Construction in progress	303,264			229,169
	12,777,882			9,181,338
Less accumulated depreciation	(1,709,992		)	(1,559,572		)
	$	11,067,890		$	7,621,766

Depreciation expense for the years ended December 31, 2014, 2013 and 2012 was $289,178, $269,790 and $216,447, respectively.

The gain on sale or write down of assets, net for the year ended December 31, 2014 includes the gain of $144,927 on the sales of Rotterdam Square, Somersville Towne Center, Lake Square Mall, South Towne Center, Camelback Colonnade and four former Meryvns' stores (See Note 14—Dispositions), $9,033 on the sale of Wilshire Boulevard (See Note 4—Investments in Unconsolidated Joint Ventures) and $1,257 on the sale of assets offset in part by a loss of $41,216 on impairment and $40,561 on the write-off of development costs. The impairment losses were due to the reduction in the estimated holding periods of the long-lived assets of several properties including Great Northern Mall, Cascade Mall, a property adjacent to Fiesta Mall and three former Mervyn's stores sold in 2014 (See Note 14—Dispositions).

The loss on sale or write down of assets, net for the year ended December 31, 2013 includes a loss of $82,197 on impairment and $1,250 on the write-off of development costs offset in part by a gain of $5,390 on the sale of assets. The loss on impairment was due to the reduction in the estimated holding periods of the long-lived assets of Promenade at Casa Grande, Rotterdam Square, Lake Square Mall and Somersville Towne Center.

The gain on sale or write down of assets, net for the year ended December 31, 2012 includes the gain of $48,484 on the sales of Chandler Village Center, Chandler Festival, Chandler Gateway and NorthPark Center (See Note 4—Investments in Unconsolidated Joint Ventures) offset in part by a loss of $19,360 on the write-off of development costs and $390 on the sale of assets.