While US household debt is slowly rising, as a percentage of GDP it’s 20 percentage points below its housing bubble peak of 100%. Nations with fast rising and high household debt-to-GDP ratios include Switzerland at 130%, Australia at 120%, Canada and Norway at 100%, New Zealand at 95%, South Korea at 92%, and Sweden at 87%. Luckily, these are all small nations. If they implode, it won’t matter.