Americans are falling behind on their credit card payments at an alarming rate, sending delinquencies and defaults surging by double-digit percentages in the past year and prompting warnings of worse to come. The value of credit card accounts at least 30 days late jumped 26 percent to $17.3 billion in October from a year earlier at 17 large credit card trusts examined by The Associated Press. That represented more than 4 percent of the total outstanding principal balances owed to the trusts on credit cards that were issued by banks such as Bank of America and Capital One and for retailers like Home Depot and Wal-Mart.