Mortgage aggregator AFG reported very strong borrowing activity in May 2013, the second month in a row when its brokers have written a record number of loans.AFG processed A$3.6 billion worth of loans last months, an increase of 13 per cent over the previous month.Demand was strongest in Western Australia, where the number of mortgages processed rose 17.7 per cent. Sales were also strong in Victoria (up 14.6 per cent), New South Wales (up 10.9 per cent) and South Australia (up 8.6 per cent).AFG's general managers of sales and operations, Mark Hewitt, said increased demand came from all groups of buyers - investors, borrowers who are refinancing and from first-home buyers.Hewitt said market conditions looked sustainable, despite the strong month-on-month growth. His evidence for this was that the average loan size, of around $400,000, has not changed over the past year, and loan-to-valuation ratios have also remained steady, at around 68 per cent.The Reserve Bank left the cash rate unchanged at 2.75 per cent yesterday. The RBA announced that its board "judged that the easier financial conditions now in place will contribute to a strengthening of growth over time, consistent with achieving the inflation target."