Update: Looking at this visualisation from p. 2 of the latest Canterbury Wellbeing Index, it seems that it is accepted that ‘High Stress’ has indeed gone up in New Zealand – and more so in Canterbury – between 2008-2010 and 2014-2015. So I guess that settles that.
It shows – at about ‘8 o’clock’ – that ‘High Stress’ has increased over that time period in New Zealand as a whole and more so in Canterbury.