Insured losses from natural disasters worldwide totalled $US15 billion ($20.31 billion) in the six months to June 30, the lowest sum since 2006, according to the latest catastrophe report from Impact Forecasting.

The US accounted for 73% of losses after thunderstorms in April, May and last month caused flood, hail, wind and tornado damage, the Aon Benfield-owned catastrophe modeller says.

Global insured losses are down 45% on the first half of last year.

The highest economic – as opposed to insured – loss was the 7.8-magnitude earthquake that killed 10,000 people in Nepal, India, Bangladesh and China.

Damage and reconstruction costs are estimated at $US10 billion ($13.54 billion), of which about 2% is covered by insurance.

Impact Forecasting warns that a below-normal first half may not be duplicated this half.

“The third quarter has historically been the costliest for the insurance industry, which is typically driven by the peak of the Atlantic hurricane season,” the report says.

The El Nino effect is forecast to reduce tropical cyclones in the Atlantic Basin but cause greater insured cyclone losses in Asia.