Deferred Credits and Other Liabilities

The following is a summary of the Company's "deferred credits and other liabilities" as presented on the Company's consolidated balance sheet. See also notes 2 and 3.



	December 31,
	2013		2012
Deferred ground lease payable	$	357,419	$	312,262
Customer prepaid rent	350,474		173,420
Above market leases for land interests, net ^(a)	276,319		58,195
Deferred credits, net ^(b)	244,537		271,123
Asset retirement obligation (see note 15)	118,403		94,953
Other liabilities	2,767		618
	$	1,349,919	$	910,571


(a)	The Company recorded $145.5 million and $17.0 million related to above-market leases for land interests under acquired wireless infrastructure for the years ended December 31, 2013 and 2012, respectively, which is inclusive of adjustments made during 2013 related to the T-Mobile purchase price allocation.


(b)	For the year ended December 31, 2012, the Company recorded deferred credits of $291.9 million related to below-market tenant leases as a result of the purchase price allocation for the NextG Acquisition. The below-market tenant leases recorded in the NextG Acquisition had a weighted-average amortization period of 11 years.

For the years ended December 31, 2013, 2012, and 2011, the Company recorded $7.2 million, $3.4 million, and $3.8 million, respectively, as a decrease to "site rental costs of operations" for the amortization of above-market leases for land interests under the Company's towers. The estimated amortization expense related to above-market leases for land interests under the Company's towers recorded to site rental costs of operations for the years ended December 31, 2014 to 2018 is as follows:



	Years Ending December 31,
	2014		2015		2016		2017		2018
Above-market leases for land interests	$	21,854	$	21,839	$	21,796	$	21,767	$	21,741

For the years ended December 31, 2013 and 2012, the Company recognized $29.6 million and $20.8 million, respectively, in site rental revenues related to the amortization of below market tenant leases. The following table summarizes the estimated annual amounts related to below-market tenant leases expected to be amortized into site rental revenues for the years ended December 31, 2014 to 2018 are as follows:



	Years Ending December 31,
	2014		2015		2016		2017		2018
Below-market tenant leases	$	28,670	$	27,395	$	27,021	$	24,243	$	21,428