what was the average other income from 2004 to 2006 in millions
increased over 4% ( 4 % ) in 2005 , costs for trucking services provided by intermodal carriers remained flat as we substantially reduced expenses associated with network inefficiencies . higher diesel fuel prices increased sales and use taxes in 2005 , which resulted in higher state and local taxes . other contract expenses for equipment maintenance and other services increased in 2005 . the 2005 january west coast storm and hurricanes katrina and rita also contributed to higher expenses in 2005 ( net of insurance settlements received ) . partially offsetting these increases was a reduction in relocation expenses as we incurred higher relocation costs associated with moving support personnel to omaha , nebraska during 2004 . non-operating items millions of dollars 2006 2005 2004 % (  % ) change 2006 v 2005 % (  % ) change 2005 v 2004 .

| <i>Millions of Dollars</i> | 2006 | 2005 | 2004 | % Change 2006 v 2005 | % Change 2005 v 2004 |
| :--- | :--- | :--- | :--- | :--- | :--- |
| Other income | $118 | $145 | $88 | (19)% | 65% |
| Interest expense | (477) | (504) | (527) | (5) | (4) |
| Income taxes | (919) | (410) | (252) | 124 | 63 |

other income 2013 lower net gains from non-operating asset sales and higher expenses due to rising interest rates associated with our sale of receivables program resulted in a reduction in other income in 2006 , which was partially offset by higher rental income for the use of our right-of-way ( including 2006 settlements of rate disputes from prior years ) and cash investment returns due to higher interest rates . in 2005 , other income increased largely as a result of higher gains from real estate sales partially offset by higher expenses due to rising interest rates associated with our sale of receivables program . interest expense 2013 lower interest expense in 2006 and 2005 was primarily due to declining weighted-average debt levels of $ 7.1 billion , $ 7.8 billion , and $ 8.1 billion in 2006 , 2005 , and 2004 , respectively . a higher effective interest rate of 6.7% ( 6.7 % ) in 2006 , compared to 6.5% ( 6.5 % ) in both 2005 and 2004 , partially offset the effects of the declining debt level . income taxes 2013 income tax expense was $ 509 million higher in 2006 than 2005 . higher pre-tax income resulted in additional taxes of $ 414 million and $ 118 million of the increase resulted from the one-time reduction in 2005 described below . our effective tax rate was 36.4% ( 36.4 % ) and 28.6% ( 28.6 % ) in 2006 and 2005 , respectively . income taxes were greater in 2005 than 2004 due to higher pre-tax income partially offset by a previously reported reduction in income tax expense . in our quarterly report on form 10-q for the quarter ended june 30 , 2005 , we reported that the corporation analyzed the impact that final settlements of pre-1995 tax years had on previously recorded estimates of deferred tax assets and liabilities . the completed analysis of the final settlements for pre-1995 tax years , along with internal revenue service examination reports for tax years 1995 through 2002 were considered , among other things , in a review and re-evaluation of the corporation 2019s estimated deferred tax assets and liabilities as of september 30 , 2005 , resulting in an income tax expense reduction of $ 118 million in .

other_income_2004 = 88
other_income_2005 = 145
other_income_2006 = 118
total_other_income = other_income_2004 + other_income_2005 + other_income_2006
answer = total_other_income / 3