Now, here's a funny thing: teachers seem to love to discuss and debate the scale and severity of the 'stress issue'. Please try to rise above this: it really doesn't matter how many other teachers, how many other schools, have problems with stress.
It is, in fact, pointless - almost perverse - to trumpet about the fact that teaching is a stressful job: this information is based on counting the incidence of stress nationwide, and is totally irrelevant to your town, to your school, to your colleagues or to you. If estate agency suddenly became terribly dangerous, then 'teaching' might slip down the league tables of stressful professions. That, though, would not make your own job any easier. Not one bit.
Stress is an individual problem affecting solitary teachers, or journalists, or librarians. The fact that teaching is statistically a more stressful profession than librarianship makes not a jot of difference: certainly not to the unfortunate individual suffering from stress, or their families.
Now, if you are a manager, there is some management logic in assessing the scale of a problem before deciding how much time and money to invest in its solution, but this investigation should take place at a local level, in terms of risk assessment in YOUR school. The fact that there is – or isn't – a national problem is entirely irrelevant: it doesn't affect your own duty of care to your colleagues.
However, for the record, here are the national key facts (these don't all specifically relate to teachers):
Around 1-in-7 people in the UK find their jobs 'very or extremely stressful' (2007)
Around half-a-million people a year believed work-related stress was 'making them ill' (2006)
Stress-related depression and anxiety affect the health of 20% of the UK working population (2006)
11 million working days lost to stress, depression, and anxiety in the UK (2006)
In the UK, teaching regularly features in the Top 5 most stressful professions
These numbers inch down or inch up year-on-year, but haven't changed significantly in 20 years.