ace usa 2019s reduction in net premiums earned in 2008 was primarily driven by the decrease in financial solutions business , as the prior year included approximately $ 170 million related to a one-time assumed loss portfolio transfer program . in addition , net premiums earned were lower in 2008 due to decreases in middle-market workers 2019 compensation business , large risk accounts and property , reflecting competitive market conditions and declining business that did not meet our selective under- writing standards . these reductions were partially offset by growth in ace usa 2019s professional liability , specialty casualty , a&h , inland marine and foreign casualty units . ace usa 2019s increase in net premiums earned in 2007 , compared with 2006 , was primarily driven by assumed loss portfolio business , as well as new business in the energy unit and growth in specialty casu- alty lines . ace usa 2019s curtailment of middle market worker 2019s compensation business partially offset these increases . ace westchester 2019s reduction in net premiums earned over the last two years was primarily due to declines in casualty and inland marine business , which resulted from competitive market conditions . this trend was partially offset by crop business growth , which benefited from generally higher commodity prices for most of 2008 and in 2007 . ace bermuda 2019s reduction in net premiums earned in 2008 , compared with 2007 , was a result of lower production , and the decrease in 2007 , compared with 2006 , was primarily due to the curtailment of financial solutions business . insurance 2013 north american 2019s loss and loss expense ratio increased in 2008 and 2007 . the following table shows the impact of catastrophe losses and prior period development on our loss and loss expense ratio for the years ended december 31 , 2008 , 2007 , and 2006. .
in 2008 what was the ratio of the north american net favorable prior period development to the catastrophe losses
insurance 2013 north american 2019s catastrophe losses were $ 298 million in 2008 , compared with $ 16 million in 2007 , and $ nil in 2006 . catastrophe losses in 2008 were primarily related to hurricanes gustav and ike . insurance 2013 north american incurred net favorable prior period development of $ 351 million in 2008 . this compares with net adverse prior period development of $ 9 million and $ 65 million in 2007 and 2006 , respectively . refer to 201cprior period development 201d for more information . the increase in the loss and loss expense ratio as adjusted in 2008 , compared with 2007 , was primarily due to changes in business mix , specifically higher premiums from the crop business , which carries a relatively high current accident year loss ratio . in addition , the 2008 loss and loss expense ratio reflects increased loss costs , including higher incurred losses for non-catastrophe events that affected the property , marine and energy business units . insurance 2013 north american 2019s policy acquisition cost ratio increased in 2008 , compared with 2007 , due in part to the inclusion of ace private risk services in 2008 , which generates a higher acquisition cost ratio than our commercial p&c business . the increase also reflects higher acquisition costs on ace westchester 2019s crop/hail business , as 2008 included more profitable results on the first quarter final settlement than in 2007 , as well as increased crop/hail production for 2008 . the first quarter settlement in 2008 generated a higher profit share commission , which added approximately 0.8 percentage points to insurance 2013 north american 2019s 2008 policy acquisition cost ratio . in addition , higher assumed loss portfolio transfer business in 2007 , which incurred low acquisition costs as is typical for these types of transactions , reduced the 2007 policy acquisition ratio by 0.2 percentage points . these increases in the 2008 policy acquisition cost ratio were partially offset by improvements at ace bermuda , primarily due to increased ceding commissions . the decrease in insurance 2013 north american 2019s 2007 policy acquisition cost ratio , compared with 2006 , was primarily related to reductions in the policy acquisition cost ratio at ace usa and ace westchester . for ace usa , the reduction reflected higher ceding commissions as well as lower premium taxes due to reassessment of obligations for premium-based assessments and guaranty funds . for ace westchester , the reduction in the policy acquisition cost ratio was primarily due to lower profit share commissions on crop business in 2007 , compared with insurance 2013 north american 2019s administrative expense ratio increased in 2008 , compared with 2007 , reflecting the inclusion of ace private risk services unit , which generates higher administrative expense ratios than our commercial p&c business , and the reduction in net premiums earned . the administrative expense ratio was stable in 2007 , compared with .