Math Quiz — NYT Learning Network

Through Math for America, I am part of an on-going collaboration with the New York Times Learning Network.  My latest contribution, a Test Yourself quiz-question, can be found here:

Test Yourself Math — November 12, 2012

This question is based on a recent report showing that average household debt is on the decline in the US.  What is the average amount of credit card debt held by adults in the United States?