During the last school year more than 6,000 leadership grade posts in maintained schools in England and Wales were advertised in The TES. And if you add in the jobs from the independent sector, the overall total was probably somewhere in the region of 7,000.
The primary sector alone generated more than 4,000 advertisements, the equivalent of one leadership post for every 50 primary teachers. As a general rule, the more senior the post, the fewer the candidates who apply.
An analysis of applications carried out by Education Data Surveys for the headteacher associations showed that an average primary school attracted just six applicants when it advertised a headship, secondary schools averaged seventeen, and special schools fewer than five.
Deputy head posts fared little better, with primary schools receiving on average seven applications, secondary schools eighteen and special schools below four (that's fewer than for headteacher posts). Applications for assistant headships in secondary schools averaged twenty three, but in the primary sector there were fewer than eight .
Perhaps not surprisingly, schools in London fared less well than those outside the capital. As a result, they were more likely to appoint an internal candidate than other schools.
Despite the slowdown in house prices in some London boroughs, the differential with many parts of the country is still too great to tempt many people to move to the capital. On the other hand, the appearance of a number of primary headships offering salaries with an upper range of more than pound;70,000 could change that. In London, salaries for headteachers in the primary and secondary sectors are closer than they have been for many years, but this is not the case in other areas of England and Wales.
There also appears to be an urban-rural divide: small country primary schools often receive few applications for headship posts. One explanation may be that becoming the centre of village life may not be such an attractive proposition if your partner has little prospect of finding a job nearby.
The large number of teachers on the leadership grades who are in their fifties - and this is particularly noticeable among headteachers - means that the demand for people to fill senior management teams is unlikely to diminish in the foreseeable future.
In general, community schools were most likely to make an appointment at the first attempt; Roman Catholic schools were the most likely to re-advertise. Specialist secondary schools often receive more applications for senior posts than their non-specialist counterparts.
Women now account for about 80 per cent of new appointments to primary headteacher posts, but they do less well in the secondary sector, where they were appointed to just one in three of the new posts on offer.
Most first-time heads are appointed in their forties, although about one in five is over 50. However, many of those on the move in their forties and fifties are experienced heads simply transferring schools. About one in 10 new primary heads was aged under 35 when appointed last year.
Evidence suggests that very few members of ethnic minority communities were appointed to leadership positions last year, even in the more junior positions. This may pose problems for the future, as schools in some areas become increasingly multicultural.
John Howson is a director of Education Data Surveys and a visiting professor at Oxford Brookes University