Source: Federal Reserve Bank of Philadelphia  

Release: FR Y-14M Large Bank Credit Card and Mortgage Data  

Units:  Percent, Not Seasonally Adjusted

Frequency:  Quarterly, End of Quarter

The average purchase (nonpromotional) APR for active general purpose credit card accounts using the APR reported at quarter end. Any reported values below 5 percent are assumed to be promotional APRs and are therefore excluded. Active credit card accounts are defined as credit card accounts that are open and have had debit, credit, or balance activity in the last 12 months.

For more detail see the methodology.