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 percent of the gradual decline in the recorded amortization expense from 2006 to 2007
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. .