Student loan debt in the United States is the second largest source of debt after mortgages. Some people believe that college education in the United States ought to be "free" and many also want to "cancel" existing student loan debt. Others see such proposals as unfair, counterproductive, and unaffordable. Please answer the following questions regarding these ideas:

1. How much total student loan debt exists in the United States? How does this number compare to mortgage debt and credit card debt? How much does each borrower owe on average and how much does each graduate owe on average?