Well, someone earning €100k (e.g. associate solicitor, senior accountant, GP doctor) will have a take home pay of €5,500.
Someone earing €50k (e.g. IT specialist, engineer bank manager) will have a take home pay of €3,150.
Someone earning €34k (e.g. young teacher, middle management) will have a take home of €2423.
Someone earing €25k (e.g. someone starting off in a graduate job) will have a take home of €1910.
Someone earing €19k (e.g. unskilled schoolleaver) will earn €1530.
Approx 67% of people earn less than 34k.
So on the basis that someone living within their means on a sensible budget will spend 1/3 of their take home pay on accomodation (rent, utilities, charges, decorating for a renter), the above categories of people should spend the following on accomodation:
Allowing €50-150 (in increments of 25) per month for utilities and charges and nil-1200 p.a. (taking it that only top end renters i.e.  and  will spend this] for decorating (most renters IMO don’t redecorate significantly), these figures should be reduced to:
 €1583 (less €150 & €100)
 €875 (less €125 & €50)
 €707 (less €100)
 €561 (less €75)
 €460 (less €50)
Next, what are the typical expectations of the above categories? I would say that:
 top end professional wants a decent house in a good area or a slick city centre pad)
 high end professional wants a good house in a good area or a good 2 bed apartments in the city centre
 a young professional wants somewhere of their own but of an alright standard.
 a young skilled worker wants something basic but not shared or good but shared
 a young unskilled worker wants somewhere shared and preferably in a nice area.
I think that of the above no  has a good chance of getting their own room in a good house in a decent area for €460 or less.
However, I think the other categories of people will be struggling to get what they want at the price they are prepared to pay. Put another way, if I was a top end professional, I should be prepared to spend no more than €1583 in rent. If that is what a top earner should be expected to pay, and a lot of landlords think that normal 1 bed apartments should be renting for this much ([=1&limit=10&id=591049]for e.g.](Property to Rent in Ireland | Daft.ie[cc_id)) then I certainly think that rents are far higher than wages on a relative level.
If anyone would care to correct or amend my figures please do so.