the following table shows the impact of catastrophe losses and related reinstatement premiums and the impact of prior period development on our consolidated loss and loss expense ratio for the periods indicated. .

2010: loss and loss expense ratio as reported: -59.2
catastrophe losses and related reinstatement premiums: -3.2
prior period development: -4.6
large assumed loss portfolio transfers: -0.3
loss and loss expense ratio adjusted: -60.3
2009: loss and loss expense ratio as reported: -58.8
catastrophe losses and related reinstatement premiums: -1.2
prior period development: -4.9
large assumed loss portfolio transfers: -0.8
loss and loss expense ratio adjusted: -61.7
2008: loss and loss expense ratio as reported: -60.6
catastrophe losses and related reinstatement premiums: -4.7
prior period development: -6.8
large assumed loss portfolio transfers: 0
loss and loss expense ratio adjusted: -62.7

we recorded net pre-tax catastrophe losses of $ 366 million in 2010 compared with net pre-tax catastrophe losses of $ 137 million and $ 567 million in 2009 and 2008 , respectively . the catastrophe losses for 2010 were primarily related to weather- related events in the u.s. , earthquakes in chile , mexico , and new zealand , and storms in australia and europe . the catastrophe losses for 2009 were primarily related to an earthquake in asia , floods in europe , several weather-related events in the u.s. , and a european windstorm . for 2008 , the catastrophe losses were primarily related to hurricanes gustav and ike . prior period development arises from changes to loss estimates recognized in the current year that relate to loss reserves first reported in previous calendar years and excludes the effect of losses from the development of earned premium from pre- vious accident years . we experienced $ 503 million of net favorable prior period development in our p&c segments in 2010 . this compares with net favorable prior period development in our p&c segments of $ 576 million and $ 814 million in 2009 and 2008 , respectively . refer to 201cprior period development 201d for more information . the adjusted loss and loss expense ratio declined in 2010 , compared with 2009 , primarily due to the impact of the crop settlements , non-recurring premium adjustment and the reduction in assumed loss portfolio business , which is written at higher loss ratios than other types of business . our policy acquisition costs include commissions , premium taxes , underwriting , and other costs that vary with , and are primarily related to , the production of premium . administrative expenses include all other operating costs . our policy acquis- ition cost ratio increased in 2010 , compared with 2009 . the increase was primarily related to the impact of crop settlements , which generated higher profit-share commissions and a lower adjustment to net premiums earned , as well as the impact of reinstatement premiums expensed in connection with catastrophe activity and changes in business mix . our administrative expense ratio increased in 2010 , primarily due to the impact of the crop settlements , reinstatement premiums expensed , and increased costs in our international operations . although the crop settlements generate minimal administrative expenses , they resulted in lower adjustment to net premiums earned in 2010 , compared with 2009 . administrative expenses in 2010 , were partially offset by higher net results generated by our third party claims administration business , esis , the results of which are included within our administrative expenses . esis generated $ 85 million in net results in 2010 , compared with $ 26 million in 2009 . the increase is primarily from non-recurring sources . our policy acquisition cost ratio was stable in 2009 , compared with 2008 , as increases in our combined insurance operations were offset by more favorable final crop year settlement of profit share commissions . administrative expenses increased in 2009 , primarily due to the inclusion of administrative expenses related to combined insurance for the full year and costs associated with new product expansion in our domestic retail operation and in our personal lines business . our effective income tax rate , which we calculate as income tax expense divided by income before income tax , is depend- ent upon the mix of earnings from different jurisdictions with various tax rates . a change in the geographic mix of earnings would change the effective income tax rate . our effective income tax rate was 15 percent in 2010 , compared with 17 percent and 24 percent in 2009 and 2008 , respectively . the decrease in our effective income tax rate in 2010 , was primarily due to a change in the mix of earnings to lower tax-paying jurisdictions , a decrease in the amount of unrecognized tax benefits which was the result of a settlement with the u.s . internal revenue service appeals division regarding federal tax returns for the years 2002-2004 , and the recognition of a non-taxable gain related to the acquisition of rain and hail . the 2009 year included a reduction of a deferred tax valuation allowance related to investments . for 2008 , our effective income tax rate was adversely impacted by a change in mix of earnings due to the impact of catastrophe losses in lower tax-paying jurisdictions . prior period development the favorable prior period development , inclusive of the life segment , of $ 512 million during 2010 was the net result of sev- eral underlying favorable and adverse movements . with respect to ace 2019s crop business , ace regularly receives reports from its managing general agent ( mga ) relating to the previous crop year ( s ) in subsequent calendar quarters and this typically results .

Questions:
what was the net favorable prior period development in 2010?
and what was it in 2008?
what was, then, the change over the years?
what was the net favorable prior period development in 2008?
and how much does that change represent in relation to this 2008 amount, in percentage?

Answers:
503
814
-311
814
38.2%