depreciation and amortization included in operating segment profit for the years ended december 31 , 2008 , 2007 and 2006 was as follows ( in millions ) : .
what was the percentage change in total rent expense from 2006 to 2007?
15 . leases future minimum rental commitments under non- cancelable operating leases in effect as of december 31 , 2008 were $ 38.2 million for 2009 , $ 30.1 million for 2010 , $ 20.9 million for 2011 , $ 15.9 million for 2012 , $ 14.3 million for 2013 and $ 29.9 million thereafter . total rent expense for the years ended december 31 , 2008 , 2007 and 2006 aggregated $ 41.4 million , $ 37.1 million and $ 31.1 million , respectively . 16 . commitments and contingencies intellectual property and product liability-related litigation in july 2008 , we temporarily suspended marketing and distribution of the durom bb acetabular component ( durom cup ) in the u.s . to allow us to update product labeling to provide more detailed surgical technique instructions to surgeons and implement a surgical training program in the u.s . following our announcement , product liability lawsuits and other claims have been asserted against us , some of which we have settled . there are a number of claims still pending and we expect additional claims will be submitted . we recorded a provision of $ 47.5 million in the third quarter of 2008 , representing management 2019s estimate of these durom cup-related claims . we increased that provision by $ 21.5 million in the fourth quarter of 2008 . the provision is limited to revisions within two years of an original surgery that occurred prior to july 2008 . these parameters are consistent with our data which indicates that cup loosenings associated with surgical technique are most likely to occur within that time period . any claims received outside of these defined parameters will be managed in the normal course and reflected in our standard product liability accruals . on february 15 , 2005 , howmedica osteonics corp . filed an action against us and an unrelated party in the united states district court for the district of new jersey alleging infringement of u.s . patent nos . 6174934 ; 6372814 ; 6664308 ; and 6818020 . on june 13 , 2007 , the court granted our motion for summary judgment on the invalidity of the asserted claims of u.s . patent nos . 6174934 ; 6372814 ; and 6664308 by ruling that all of the asserted claims are invalid for indefiniteness . on august 19 , 2008 , the court granted our motion for summary judgment of non- infringement of certain claims of u.s . patent no . 6818020 , reducing the number of claims at issue in the suit to five . we continue to believe that our defenses against infringement of the remaining claims are valid and meritorious , and we intend to defend this lawsuit vigorously . in addition to certain claims related to the durom cup discussed above , we are also subject to product liability and other claims and lawsuits arising in the ordinary course of business , for which we maintain insurance , subject to self- insured retention limits . we establish accruals for product liability and other claims in conjunction with outside counsel based on current information and historical settlement information for open claims , related fees and claims incurred but not reported . while it is not possible to predict with certainty the outcome of these cases , it is the opinion of management that , upon ultimate resolution , liabilities from these cases in excess of those recorded , if any , will not have a material adverse effect on our consolidated financial position , results of operations or cash flows . government investigations in march 2005 , the u.s . department of justice through the u.s . attorney 2019s office in newark , new jersey commenced an investigation of us and four other orthopaedic companies pertaining to consulting contracts , professional service agreements and other agreements by which remuneration is provided to orthopaedic surgeons . on september 27 , 2007 , we reached a settlement with the government to resolve all claims related to this investigation . as part of the settlement , we entered into a settlement agreement with the u.s . through the u.s . department of justice and the office of inspector general of the department of health and human services ( the 201coig-hhs 201d ) . in addition , we entered into a deferred prosecution agreement ( the 201cdpa 201d ) with the u.s . attorney 2019s office for the district of new jersey ( the 201cu.s . attorney 201d ) and a corporate integrity agreement ( the 201ccia 201d ) with the oig- hhs . we did not admit any wrongdoing , plead guilty to any criminal charges or pay any criminal fines as part of the settlement . we settled all civil and administrative claims related to the federal investigation by making a settlement payment to the u.s . government of $ 169.5 million . under the terms of the dpa , the u.s . attorney filed a criminal complaint in the u.s . district court for the district of new jersey charging us with conspiracy to commit violations of the anti-kickback statute ( 42 u.s.c . a7 1320a-7b ) during the years 2002 through 2006 . the court deferred prosecution of the criminal complaint during the 18-month term of the dpa . the u.s . attorney will seek dismissal of the criminal complaint after the 18-month period if we comply with the provisions of the dpa . the dpa provides for oversight by a federally-appointed monitor . under the cia , which has a term of five years , we agreed , among other provisions , to continue the operation of our enhanced corporate compliance program , designed to promote compliance with federal healthcare program z i m m e r h o l d i n g s , i n c . 2 0 0 8 f o r m 1 0 - k a n n u a l r e p o r t notes to consolidated financial statements ( continued ) %%transmsg*** transmitting job : c48761 pcn : 060000000 ***%%pcmsg|60 |00012|yes|no|02/24/2009 06:10|0|0|page is valid , no graphics -- color : d| .