Last year's census recorded for the first time the reasons why properties are vacant.
Up to half of the properties recorded as 'vacant' in the capital could be short-term lets.
Last year's census recorded for the first time the reasons why properties are vacant, with 'rental properties' making up over 33,000 of the 130,000 vacant dwellings nationally.
The CSO notes the figure could include short-term lettings and properties that were between lets but may not have been advertised.