This type of chart is trotted out constantly these days to show that American households are in fabulous shape when it comes to their ability to service their blistering record debts. The red line in the chart shows household debt-service payments (combined monthly payments on mortgages, credit cards, auto loans, and student loans) as a percent of disposable (after-tax) income. Since 1980, the ratio has ranged from 9.9% to 13.2%. It hit that top in Q4 2007 just before it all came apart. Ten years later, it was at 10.3%. Hence the conclusion that households won't have any trouble servicing their record debts. In a moment, we'll get to the trap in this conclusion.