The general insurance industry suffered an aggregate underwriting loss in 2011 and will struggle to make a profit this year, according to a new industry study.Respondents to the JP Morgan Deloitte General Insurance Industry Survey, which was released yesterday, reported an average combined ratio of 98 per cent on personal policy classes and 106 per cent on commercial classes. The combined ratio calculates claims plus underwriting expenses as a percentage of premium income, and a combined ratio of over 100 per cent indicates an underwriting loss.Commercial property was the big loss-maker, with an average combined ratio of 134 per cent. Home and contents had an average combined ratio of 107 per cent. Together, these policy classes account for about 25 per cent of general insurance underwriting.The underwriting losses were a result of last year's severe weather events.Respondents said they expected to do better this year and forecasted an average combined ratio of 92 per cent on both personal and commercial classes.However, JP Morgan and Deloitte have adjusted these forecasts and come up their own estimates. These forecast underwriting losses on New South Wales compulsory third-party cover, commercial property, workers' compensation and professional indemnity.Deloitte Actuarial partner Elaine Collins said the JP Morgan and Deloitte forecasts had adjusted the industry forecasts for premium rate changes, claims inflation and claims frequency.Premium rates went up by an average of five per cent for personal policy classes and by three per cent for commercial classes last year. The big increases were in home and contents (up 10 per cent) and commercial property (up seven per cent).The industry expects to increase premiums on personal classes by an average of seven per cent this year, and by five per cent on commercial classes. Home and contents premiums will rise by 13 per cent and commercial property by nine per cent.Rising reinsurance costs will eat an average of 2.5 per cent of these premium increases.