american tower corporation and subsidiaries notes to consolidated financial statements 2014 ( continued ) the company has selected december 1 as the date to perform its annual impairment test . in performing its 2005 and 2004 testing , the company completed an internal appraisal and estimated the fair value of the rental and management reporting unit that contains goodwill utilizing future discounted cash flows and market information . based on the appraisals performed , the company determined that goodwill in its rental and management segment was not impaired . the company 2019s other intangible assets subject to amortization consist of the following as of december 31 , ( in thousands ) : .
what was the percentage of the increase in the customer intangible asset from 2004 to 2005
the company amortizes its intangible assets over periods ranging from three to fifteen years . amortization of intangible assets for the years ended december 31 , 2005 and 2004 aggregated approximately $ 136.0 million and $ 97.8 million , respectively ( excluding amortization of deferred financing costs , which is included in interest expense ) . the company expects to record amortization expense of approximately $ 183.6 million , $ 178.3 million , $ 174.4 million , $ 172.7 million and $ 170.3 million , for the years ended december 31 , 2006 , 2007 , 2008 , 2009 and 2010 , respectively . these amounts are subject to changes in estimates until the preliminary allocation of the spectrasite purchase price is finalized . 6 . notes receivable in 2000 , the company loaned tv azteca , s.a . de c.v . ( tv azteca ) , the owner of a major national television network in mexico , $ 119.8 million . the loan , which initially bore interest at 12.87% ( 12.87 % ) , payable quarterly , was discounted by the company , as the fair value interest rate at the date of the loan was determined to be 14.25% ( 14.25 % ) . the loan was amended effective january 1 , 2003 to increase the original interest rate to 13.11% ( 13.11 % ) . as of december 31 , 2005 and 2004 , approximately $ 119.8 million undiscounted ( $ 108.2 million discounted ) under the loan was outstanding and included in notes receivable and other long-term assets in the accompanying consolidated balance sheets . the term of the loan is seventy years ; however , the loan may be prepaid by tv azteca without penalty during the last fifty years of the agreement . the discount on the loan is being amortized to interest income 2014tv azteca , net , using the effective interest method over the seventy-year term of the loan . simultaneous with the signing of the loan agreement , the company also entered into a seventy year economic rights agreement with tv azteca regarding space not used by tv azteca on approximately 190 of its broadcast towers . in exchange for the issuance of the below market interest rate loan discussed above and the annual payment of $ 1.5 million to tv azteca ( under the economic rights agreement ) , the company has the right to market and lease the unused tower space on the broadcast towers ( the economic rights ) . tv azteca retains title to these towers and is responsible for their operation and maintenance . the company is entitled to 100% ( 100 % ) of the revenues generated from leases with tenants on the unused space and is responsible for any incremental operating expenses associated with those tenants. .