@resjudicata
As long as you are measuring average of all housing against average of all salaries this data should be absolutely fine and tells alot.
Perhaps from a pure data and statistics perspective, that is true.
I am speaking from a personal finance perspective (given the sub), where the predominant inquiry people have of this kind of information is: "is where I live going to be affordable for me or not - and how has that changed".
That is where a national average is not useful, because residential property buyers aren't economic actors who will move across the country just because the house price/salary ratio becomes more attractive.
Whether someone can afford a house depends on credit conditions because most houses are bought on credit. Credit conditions are based now on salary (given PRA regulation) - but most people live near where they work. That is why what is important for those readers is, especially for those moving for a job, what the average salary
in their region is, compared to house prices there.
At the end of the day it's about your personal budget and disposable, given all the posts we get on this day-in, day-out.
Given the variances across the country in residential property prices and factors (I didn't spell it out but basically compare the London market to the North West - or even the SW1X market to N1 or E8) a national average isn't going to help you with that question.
That's why I question the usefulness of this kind of thing on this sub - and why it's probably best suited for comment elsewhere. Not to want to rubbish the OP's effort though, because there is certainly a point to be made about house pricing and the rate of change of capital values vis-a-vis average earnings!