The index measure the proportion of after-tax income is required to meet the first year's mortgage payments for an "average" first-time buyer working couple, each on average earnings.
It shows the national affordability level remains stable at 19.3% of net income for a working couple buying the average property.
While it is expected that affordability levels will rise to 19.6% this month, it is still below the peak of more than 26% recorded during the boom.
In Dublin, however, the average working couple needs just over 24% of their net income to fund their mortgage. This is due to rising house prices, which are up 13.7% in the latter half of 2013.
The average price of a home in Dublin is now €234,500, according to the index. Outside the capital, affordability levels have stayed relatively stable at 16.7%.