The American middle class is falling deeper into debt to maintain a middle-class lifestyle.

Cars, college, houses and medical care have become steadily more costly, but incomes have been largely stagnant for two decades, despite a recent uptick. Filling the gap between earning and spending is an explosion of finance into nearly every corner of the consumer economy.

Consumer debt, not counting mortgages, has climbed to $4 trillion—higher than it has ever been even after adjusting for inflation. Mortgage debt slid after the financial crisis a decade ago but is rebounding.

Student debt totaled about $1.5 trillion last year, exceeding all other forms of consumer debt except mortgages.

Auto debt is up nearly 40% adjusting for inflation in the last decade to $1.3 trillion. And the average loan for new cars is up an inflation-adjusted 11% in a decade, to $32,187, according to an analysis of data from credit-reporting firm Experian.