A secular shift in the use of credit cards as a tool of household finance may be underway, with a decline for the fourth consecutive month in the value of credit card balances in October. This is the first such run of declines in this measure of the credit card market since the Reserve Bank of Australia began collating the data in 1985.Credit card balances increased 2.8 per cent to A$49.1 billion at the end of October 2011, a rise similar to the rate of inflation.Mike Ebstein of MWE Consulting notes in his monthly report on the payments card market that the average rate of growth in balances, on a 12-month basis, has dropped for 10 months in a row.One factor in the decline in balances is the reduced use of cash advances. Over the last year cash advances represented four per cent of the value of monthly transactions on credit cards, down from around seven per cent of transactions five years ago (close to twice the ratio in the late 1990s).Another is the declining use of credit cards as a payment tool, as households switch to debit cards or other methods including cash.Ebstein estimated the average annual spend per credit card account at $16,034 in October 2011, a rise of 3.5 per cent over a year. Ebstein attributes most of this growth to charge and commercial cards.He attributed this to "reduced expenditure in areas such as consumer durables and travel as well as altering payment practices in which debit has been replacing cash and credit cards."The RBA produced revised data this month on the share of payments between debit cards and credit cards.These now put the market share of debit cards, as a percentage of the wider payment card market, at 39.1 per cent in October 2011, up from 33.8 per cent three years ago.