(Reuters) - U.S. household debt hit $12.29 trillion in the second quarter, up $434 billion from a year earlier as auto loans and credit card debt increased, a Federal Reserve Bank of New York survey showed on Tuesday.

Some 4.8 percent of the outstanding debt was in some stage of delinquency, down from 5.6 percent from a year ago, according to the quarterly household debt and credit report.

Auto debt was $1.10 trillion, up $97 billion from a year earlier, while the aggregate credit card limit increased for the 14th straight quarter, reflecting Americans' easier access to credit as the 2007-2009 financial crisis fades.

Mortgage debt was $8.36 trillion, up $246 billion from last year, while student loan debt was $1.26 trillion, up $69 billion.

(Reporting by Jonathan Spicer; Editing by Chizu Nomiyama)