investment policy , which is described more fully in note 15 employee benefit plans in the notes to consolidated financial statements in item 8 of this report .we calculate the expense associated with the pension plan and the assumptions and methods that we use include a policy of reflecting trust assets at their fair market value .on an annual basis , we review the actuarial assumptions related to the pension plan , including the discount rate , the rate of compensation increase and the expected return on plan assets .the discount rate and compensation increase assumptions do not significantly affect pension expense .however , the expected long-term return on assets assumption does significantly affect pension expense .our expected long- term return on plan assets for determining net periodic pension expense has been 8.25% ( 8.25 % ) for the past three years .the expected return on plan assets is a long-term assumption established by considering historical and anticipated returns of the asset classes invested in by the pension plan and the allocation strategy currently in place among those classes .while this analysis gives appropriate consideration to recent asset performance and historical returns , the assumption represents a long-term prospective return .we review this assumption at each measurement date and adjust it if warranted .for purposes of setting and reviewing this assumption , 201clong- term 201d refers to the period over which the plan 2019s projected benefit obligation will be disbursed .while year-to-year annual returns can vary significantly ( rates of return for the reporting years of 2009 , 2008 , and 2007 were +20.61% ( +20.61 % ) , -32.91% ( -32.91 % ) , and +7.57% ( +7.57 % ) , respectively ) , the assumption represents our estimate of long-term average prospective returns .our selection process references certain historical data and the current environment , but primarily utilizes qualitative judgment regarding future return expectations .recent annual returns may differ but , recognizing the volatility and unpredictability of investment returns , we generally do not change the assumption unless we modify our investment strategy or identify events that would alter our expectations of future returns .to evaluate the continued reasonableness of our assumption , we examine a variety of viewpoints and data .various studies have shown that portfolios comprised primarily of us equity securities have returned approximately 10% ( 10 % ) over long periods of time , while us debt securities have returned approximately 6% ( 6 % ) annually over long periods .application of these historical returns to the plan 2019s allocation of equities and bonds produces a result between 8% ( 8 % ) and 8.5% ( 8.5 % ) and is one point of reference , among many other factors , that is taken into consideration .we also examine the plan 2019s actual historical returns over various periods .recent experience is considered in our evaluation with appropriate consideration that , especially for short time periods , recent returns are not reliable indicators of future returns , and in many cases low returns in recent time periods are followed by higher returns in future periods ( and vice versa ) .acknowledging the potentially wide range for this assumption , we also annually examine the assumption used by other companies with similar pension investment strategies , so that we can ascertain whether our determinations markedly differ from other observers .in all cases , however , this data simply informs our process , which places the greatest emphasis on our qualitative judgment of future investment returns , given the conditions existing at each annual measurement date .the expected long-term return on plan assets for determining net periodic pension cost for 2009 was 8.25% ( 8.25 % ) , unchanged from 2008 .during 2010 , we intend to decrease the midpoint of the plan 2019s target allocation range for equities by approximately five percentage points .as a result of this change and taking into account all other factors described above , pnc will change the expected long-term return on plan assets to 8.00% ( 8.00 % ) for determining net periodic pension cost for 2010 .under current accounting rules , the difference between expected long-term returns and actual returns is accumulated and amortized to pension expense over future periods .each one percentage point difference in actual return compared with our expected return causes expense in subsequent years to change by up to $ 8 million as the impact is amortized into results of operations .the table below reflects the estimated effects on pension expense of certain changes in annual assumptions , using 2010 estimated expense as a baseline .change in assumption ( a ) estimated increase to 2010 pension expense ( in millions ) .
[['change in assumption ( a )', 'estimatedincrease to 2010pensionexpense ( inmillions )'], ['.5% ( .5 % ) decrease in discount rate', '$ 10'], ['.5% ( .5 % ) decrease in expected long-term return on assets', '$ 18'], ['.5% ( .5 % ) increase in compensation rate', '$ 3']]
( a ) the impact is the effect of changing the specified assumption while holding all other assumptions constant .we currently estimate a pretax pension expense of $ 41 million in 2010 compared with pretax expense of $ 117 million in 2009 .this year-over-year reduction was primarily due to the amortization impact of the favorable 2009 investment returns as compared with the expected long-term return assumption .our pension plan contribution requirements are not particularly sensitive to actuarial assumptions .investment performance has the most impact on contribution requirements and will drive the amount of permitted contributions in future years .also , current law , including the provisions of the pension protection act of 2006 , sets limits as to both minimum and maximum contributions to the plan .we expect that the minimum required contributions under the law will be zero for 2010 .we maintain other defined benefit plans that have a less significant effect on financial results , including various .

Question: the decrease in pretax pension expenses was what percentage of a decrease?
Answer: 64.9%