As the personal savings rate sank near an all-time low, credit card balances jumped 15% year over year, according to the latest quarterly report from the Federal Reserve Bank of New York, notching the largest increase in more than 20 years.More from Personal Finance:Here's the best way to pay down high-interest debt63% of Americans are living paycheck to paycheck'Risky behaviors' are causing credit scores to level offHere's the best way to pay down high-interest debt63% of Americans are living paycheck to paycheck'Risky behaviors' are causing credit scores to level offNearly half, or 46%, of credit cardholders carry debt from month to month on at least one card, up from 39% last year, according to a new report by Bankrate.com.Not only can carrying a balance lower your credit score, but sky-high annual percentage rates also make credit cards one of the most expensive ways to borrow money."If you don't take steps to knock that debt down, it will only get more expensive," Schulz said.Making the best use of a balance transfer boils down to making those payments on time and aggressively paying down the balance during the introductory period, according to Schulz."