The Icelandic Central Bank said that for nearly a quarter of all households in the country, the total debt service for mortgages, car loans and overdraft loans had exceeded 40% of disposable income, commonly considered the "danger limit" for total debt service.

FORBES: Global Economy

They add up to disposable personal income, and then other adjustments are needed to take you the rest of the way to total GDP.

FORBES: The Income Side of GDP