(b) The Senior Secured Notes, Series 2009-1 consist of $123.8 million of principal as of March 31, 2013 that amortizes during the period beginning January 2010 and ending in 2019, and $70.0 million of principal that amortizes during the period beginning in 2019 and ending in 2029.
(c) The Senior Secured Tower Revenue Notes Series 2010-1, 2010-2 and 2010-3 have principal amounts of $300.0 million, $350.0 million, and $1,250.0 million with anticipated repayment dates of 2015, 2017, and 2020, respectively.
(d) The Senior Secured Tower Revenue Notes Series 2010-4, 2010-5 and 2010-6 have principal amounts of $250.0 million, $300.0 million and $1,000.0 million with anticipated repayment dates of 2015, 2017 and 2020, respectively.
(e) The WCP Secured Wireless Site Contracts Revenue Notes, Series 2010-1 ("WCP Securitized Notes") were assumed in connection with the WCP acquisition. If WCP Securitized Notes are not repaid in full by their anticipated repayment dates in 2015, the applicable interest rate increases by an additional approximately 5% per annum. If the WCP Securitized Notes are not repaid in full by their rapid amortization date of 2017, monthly principal payments commence.(f) Excludes restricted cash. Sustaining capital expenditures for the three months ended March 31, 2013 and 2012 is computed as follows:
|For the Three Months Ended|
|(in millions)||March 31, 2013||March 31, 2012|
|Less: Land purchases||16.0||27.9|
|Less: Tower improvements and other||57.8||25.9|
|Less: Construction of towers||35.7||7.0|
|Sustaining capital expenditures||$6.9||$4.3|