NEW YORK (Bloomberg) ? US property casualty insurers used the lowest proportion of premiums for expenses and claims in two decades after losses plunged last quarter because of calmer weather.

Insurers used 90.6 cents of every $1 in premiums collected to pay claims and expenses in the third quarter, the lowest ratio since Jersey City, New Jersey-based insurance data provider ISO began keeping records in 1986, the Property Casualty Insurers Association of America said in a statement today.

The industry took in $9.3 billion more in premiums than it paid out in claims and expenses during the last quarter, compared with a $15.2 billion loss during the same period a year ago, when Hurricanes Katrina and Rita battered the US Gulf Coast, according to the report. Insured catastrophe losses were $1.3 billion, compared with $48 billion a year earlier.

?Natural catastrophes still pose a huge threat to consumers and businesses along the Gulf and Atlantic coasts,? said economist Genio Staranczak of the Des Plaines, Illinois-based Property Casualty Insurers Association. ?We view this development as an anomaly rather than a trend.?

Insurers such as American International Group Inc., the world?s largest insurer, and St. Paul Travelers Cos., the second- largest US commercial insurer, saw profit surge after neither of this season?s two major Atlantic hurricanes made landfall in the US.