That's somewhat different to my experience. Anyone I know who's bought recently has bought with at least 1 other person, be it family, friend or partner. I haven't heard of 1 person who has bought solo. (oh actually I have, 1 person, a doctor)
In my experience about 50% buy with a partner and about 50% buy solo with the help of parents and family, like being a guarantor, but not actually paying the mortgage.
Just an observation, I could be completely wrong or my experience might not be statistically significant.
i dont know how that figure could be arrived at, one way could be to check which properties in say dublin had no electricity supply or the bill for the properties electricity was less than a hundred euro in preceding year meaning that no one was likely to be living in it but owner was just using minimum electricity when inspecting,staying odd night etc. Or maybe landline phone usuage per dwelling could indicate the true figure.
That would be a bad way to measure it. Many people nowadays are opting not to get a land line, specially in rented accommodation, as people have mobiles.
Over the last 4 years, the number of phone lines has remained static, while in the same period the population has grown by some 10%.