A leading insurer says that 2015 saw the lowest costs from natural disasters for six years as the El Nino weather phenomenon reduced hurricane activity in the North Atlantic.

The year's most devastating disaster was the earthquake in Nepal, but only a fraction of the resulting losses was insured.

Insurer Munich Re said Monday that both insured losses and overall costs resulting from disasters were the lowest since 2009. It said that there were some $27 billion in insured losses, while overall costs — including losses not covered by insurance — totaled $90 billion.

The costliest event for the insurance industry was a series of winter storms that hit the northeastern U.S. and Canada in February. They generated insured losses of $2.1 billion and total losses of $2.8 billion.