investment advisory revenues earned on the other investment portfolios that we manage decreased $ 44 million , or 8.5% ( 8.5 % ) , to $ 477.8 million in 2009 .
average assets in these portfolios were $ 129.5 billion during 2009 , down $ 12.6 billion or 9% ( 9 % ) from 2008 .
other investment portfolio assets under management increased $ 46.7 billion during 2009 , including $ 36.5 billion in market gains and income and $ 10.2 billion of net inflows , primarily from institutional investors .
net inflows include $ 1.3 billion transferred from the stock and blended asset mutual funds during 2009 .
administrative fees decreased $ 35 million , or 10% ( 10 % ) , to $ 319 million in 2009 .
this change includes a $ 4 million decrease in 12b-1 distribution and service fees recognized on lower average assets under management in the advisor and r classes of our sponsored mutual funds and a $ 31 million reduction in our mutual fund servicing revenue , which is primarily attributable to our cost reduction efforts in the mutual fund and retirement plan servicing functions .
changes in administrative fees are generally offset by similar changes in related operating expenses that are incurred to provide services to the funds and their investors .
our largest expense , compensation and related costs , decreased $ 42 million , or 5% ( 5 % ) , from 2008 to $ 773 million in 2009 .
the largest part of this decrease is attributable to a $ 19 million reduction in our annual bonus program .
reductions in the use of outside contractors lowered 2009 costs $ 14 million with the remainder of the cost savings primarily attributable to the workforce reduction and lower employee benefits and other employment expenses .
average headcount in 2009 was down 5.4% ( 5.4 % ) from 2008 due to attrition , retirements and our workforce reduction in april 2009 .
advertising and promotion expenditures were down $ 31 million , or 30% ( 30 % ) , versus 2008 due to our decision to reduce spending in response to lower investor activity in the 2009 market environment .
depreciation expense and other occupancy and facility costs together increased $ 4 million , or 2.5% ( 2.5 % ) compared to 2008 , as we moderated or delayed our capital spending and facility growth plans .
other operating expenses decreased $ 33 million , or 18% ( 18 % ) from 2008 , including a decline of $ 4 million in distribution and service expenses recognized on lower average assets under management in our advisor and r classes of mutual fund shares that are sourced from financial intermediaries .
our cost control efforts resulted in the remaining expense reductions , including lower professional fees and travel and related costs .
our non-operating investment activity resulted in net losses of $ 12.7 million in 2009 and $ 52.3 million in 2008 .
the improvement of nearly $ 40 million is primarily attributable to a reduction in the other than temporary impairments recognized on our investments in sponsored mutual funds in 2009 versus 2008 .
the following table details our related mutual fund investment gains and losses ( in millions ) during the two years ended december 31 , 2009. .

2008
2009
Change
Other than temporary impairments recognized
$(91.3)
$(36.1)
$55.2
Capital gain distributions received
5.6
2.0
(3.6)
Net gain (loss) realized on fund dispositions
(4.5)
7.4
11.9
Net loss recognized on fund holdings
$(90.2)
$(26.7)
$63.5

lower income of $ 16 million from our money market holdings due to the significantly lower interest rate environment offset the improvement experienced with our fund investments .
the 2009 provision for income taxes as a percentage of pretax income is 37.1% ( 37.1 % ) , down from 38.4% ( 38.4 % ) in 2008 .
our 2009 provision includes reductions of prior years 2019 tax provisions and discrete nonrecurring benefits that lowered our 2009 effective tax rate by 1.0% ( 1.0 % ) .
c a p i t a l r e s o u r c e s a n d l i q u i d i t y .
during 2010 , stockholders 2019 equity increased from $ 2.9 billion to $ 3.3 billion .
we repurchased nearly 5.0 million common shares for $ 240.0 million in 2010 .
tangible book value is $ 2.6 billion at december 31 , 2010 , and our cash and cash equivalents and our mutual fund investment holdings total more than $ 1.5 billion .
given the availability of these financial resources , we do not maintain an available external source of liquidity .
t .
rowe price group annual report 2010 .

Question: Analyse this data from a financial earnings document. by what percent did the provision for income taxes as a percentage of pretax income decrease between 2008 and 2009?
Choices:
0
75.5
-36.7
1.3
-35.6
Correct choice index: 3