Consumers gave their credit and charge cards a heavy workout in July but, looking longer term, growth in debit card usage continues to outpace the use of credit.According to Reserve Bank payment data released yesterday, the number of purchases made on debit cards increased by 7.6 per cent in July, and the value of those purchases rose by 11.5 per cent.The number of purchases made on credit and charge cards increased by 15.5 per cent in July, and the value of those purchases increased by 13.2 per cent.Year on year, the number of debit card transactions in July was up 14.3 per cent on July last year, and the value of those transactions was up 12.2 per cent.The number of credit and charge card transactions in July was up 11.8 per cent on July last year, and the value of those transactions was up eight per cent.According to MWE Consulting, debit cards account for 41.6 per cent of card purchases, compared with 39.8 per cent a year ago.The number of debit card accounts grew by 5.7 per cent over the 12 months to July, while the number of credit and charge card accounts grew by 2.3 per cent over the same period.In a presentation yesterday, Myer said its Myer Visa card, issued by GE Money, had an annual average spend of A$12,000.The average credit card spend, according to MWE, is a little over $15,000.