Concentration of Credit Risk (Tables)

3 Months Ended

Mar. 31, 2013

Summary of Significant Customers and Percentage of Total Revenue for Specified Time Periods Derived from Such Customers

The following is a list of significant customers (representing at least 10% of revenue for the periods reported) and the percentage of total revenue for the specified time periods derived from such customers:


Site Leasing Revenue	For the three months ended March 31,
	2013			2012
Sprint		25.3	%		23.6	%
AT&T		21.3	%		25.6	%
T-Mobile		13.6	%		10.4	%
Verizon		11.9	%		14.6	%

Site Development Revenue	For the three months ended March 31,
	2013			2012
Ericsson, Inc.		40.4	%		14.7	%
Alcatel-Lucent		11.3	%		3.9	%
Nsoro		5.9	%		25.8	%
T-Mobile		5.6	%		15.9	%

- Definition

Tabular disclosure of the nature of a concentration, a benchmark to which it is compared, and the percentage that the risk is to the benchmark.

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