The pace at which debit cards are overtaking credit cards as preferred payment instruments may be slowing down.The latest Reserve Bank payment figures show that consumers used debit cards to make 359.9 million purchases worth A$18.6 billion in February, while they used credit and charge cards to make 193.4 million purchases, worth $24.8 billion.Debit accounted for 42.9 per cent of the value of purchases in February, while credit and charge accounted for 57.1 per cent.The use of debit cards has been growing, relative to credit and charge, for some years. According to MWE Consulting, debit's share of total card spend was around 36 per cent in 2010 and has grown by about one percentage point a year since then.But over the 12 months to February the growth in debit's share was around half the long-term trend rate - about 50 basis points.Consumers make more purchases on their debit cards but they tend to make the bigger purchases on credit. The average debit card transaction was worth $51.70 in February, while the average credit card transaction was worth $128.30.Spending on credit cards went through a period of little or no growth between 2010 and 2014 as consumers shied away from accumulating personal debt. Over the past couple of years spending has picked up again but card balances have remained steady. Consumers are using their credit cards for payments, making use of reward points, free insurance and other benefits, but not allowing their balances to revolve.The number of credit card accounts continues to grow at the same rate as growth in the number of debit accounts. There are 16.4 million credit and charge cards in the market - a 3.3 per cent increase over the 12 months to February.There 41.8 million debit cards in the market - a 3.2 per cent increase over the past 12 months.MWE said the rate of growth in credit and charge card numbers has not been higher than the rate of growth in debit accounts since 2008.