In the June 2015 quarter the proportion of household income required to meet loan repayments decreased by 0.5 percentage points to 30.3 per cent, according to the latest Adelaide Bank/Real Estate Institute of Australia Housing Affordability report.Part of the momentum has come from the cooling in demand in WA and Queensland as the mining boom winds down. However, on the report's numbers, South Australia showed the greatest improvement in affordability across the country with the proportion of income required to meet loan repayments going down 2.9 percentage points, to 25.5 per cent.    The Affordability Report noted that during this quarter the number of first home buyers increased by 8.1 per cent to 24,869 - a decrease of 3.8 per cent from twelve months ago. First home buyers now make up 15.7 per cent of the owner-occupier market, well below the long-run average of 19.8 per cent, the report noted.Year on year, the biggest increase in the average loan size was recorded in New South Wales which retained the crown of "least affordable State", according to Adelaide Bank.  The Northern Territory recorded the biggest annual improvement in housing affordability, with the proportion of income required to meet loan repayments decreasing 2.8 percentage points. "The improvement in housing affordability is attributable to the rise in the national median weekly family income and a drop in interest rates," said Damian Percy, general manager at Adelaide Bank.  The cut in official interest rates during the second quarter of 2015 resulted in an average monthly loan repayment of $2,128 - a drop of 1.4 per cent over the quarter but an increase of 0.4 per cent when compared to the corresponding quarter of the previous year.