The number of Australians who own their home outright has fallen over the past decade, as more older Australians remain in debt for longer.Analysis of the most recent Australian Bureau of Statistics Household Expenditure Survey, in the latest Reserve Bank Bulletin, shows that 37.2 per cent of the population have a mortgage, 33.5 per cent own their home outright and 29.3 per cent are renters.The RBA examined the change in expenditure shares from 2003/04 to 2009/10. Since 2003/04 the proportion of renters has increased 1.1 percentage points, the proportion of mortgage holders has increased 1.2 percentage points and that of outright owners has fallen 2.3 points.According to the RBA: "This change has largely been driven by the propensity of older households to remain in debt for longer, as well as an increase in the number of households with investment property."As a consequence, the country's housing debt-to-income ratio increased from 79 per cent in 2003/04 to 98 per cent in 2009/10.There were other factors at play too. Nationwide, house prices increased by around 19 per cent, relative to the consumer price index, over this period.Increased spending on housing may be one of the reasons retail is in the doldrums. A re-allocation away from spending on durable and non-durable goods towards services was found to be widespread across all income and education groups.