compared to 2007 . we reduced personal injury expense by $ 80 million in 2007 as a result of fewer than expected claims and lower than expected average settlement costs . in 2008 , we reduced personal injury expense and asbestos-related costs $ 82 million based on the results of updated personal injury actuarial studies and a reassessment of our potential liability for resolution of current and future asbestos claims . in addition , environmental and toxic tort expenses were $ 7 million lower in 2008 compared to 2007 . other costs were lower in 2007 compared to 2006 driven primarily by a reduction in personal injury expense . actuarial studies completed during 2007 resulted in a reduction in personal injury expense of $ 80 million , which was partially offset by an adverse development with respect to one claim . settlement of insurance claims in 2007 related to hurricane rita , and higher equity income also drove expenses lower in 2007 versus 2006 . conversely , the year-over-year comparison was affected by the settlement of insurance claims totaling $ 23 million in 2006 related to the january 2005 west coast storm and a $ 9 million gain in 2006 from the sale of two company-owned airplanes . non-operating items millions of dollars 2008 2007 2006 % (  % ) change 2008 v 2007 % (  % ) change 2007 v 2006 .
in 2008 what was the ratio of the reduction of the personal injury expense and asbestos-related costs to the environmental and toxic tort expenses
other income 2013 other income decreased in 2008 compared to 2007 due to lower gains from real estate sales and decreased returns on cash investments reflecting lower interest rates . higher rental and licensing income and lower interest expense on our sale of receivables program partially offset the decreases . lower net gains from non-operating asset sales ( primarily real estate ) drove the reduction in other income in 2007 . recognition of rental income in 2006 from the settlement of a rent dispute also contributed to the year-over-year decrease in other income . cash investment returns increased $ 21 million due to larger cash balances and higher interest rates . interest expense 2013 interest expense increased in 2008 versus 2007 due to a higher weighted-average debt level of $ 8.3 billion , compared to $ 7.3 billion in 2007 . a lower effective interest rate of 6.1% ( 6.1 % ) in 2008 , compared to 6.6% ( 6.6 % ) in 2007 , partially offset the effects of the higher weighted-average debt level . an increase in the weighted-average debt levels to $ 7.3 billion from $ 7.1 billion in 2006 generated higher interest expense in 2007 . a lower effective interest rate of 6.6% ( 6.6 % ) in 2007 , compared to 6.7% ( 6.7 % ) in 2006 , partially offset the effects of the higher debt level . income taxes 2013 income taxes were higher in 2008 compared to 2007 , driven by higher pre-tax income . our effective tax rates were 36.1% ( 36.1 % ) and 38.4% ( 38.4 % ) in 2008 and 2007 , respectively . the lower effective tax rate in 2008 resulted from several reductions in tax expense related to federal audits and state tax law changes . in addition , the effective tax rate in 2007 was increased by illinois legislation that increased deferred tax expense in the third quarter of 2007 . income taxes were $ 235 million higher in 2007 compared to 2006 , due primarily to higher pre-tax income and the effect of new tax legislation in the state of illinois that changed how we determine the amount of our income subject to illinois tax . the illinois legislation increased our deferred tax expense by $ 27 million in 2007 . our effective tax rates were 38.4% ( 38.4 % ) and 36.4% ( 36.4 % ) in 2007 and 2006 , respectively. .