The rest have degrees or professional or higher-level technical training, the survey of staff by the Further Education Funding Council revealed.
The figures are published in a new report on standards of vocational qualifications in which inspectors criticise the out-of-date industrial experience of many staff and urge colleges to invest more effort in updating lecturers' skills.
The inspectors point out that teachers are generally regarded as adequately qualified, but warn that many colleges keep inadequate records on their employees' academic and work backgrounds.
The report says: "The experience of many teachers is out of date. Some staff teaching general national vocational qualifications who come from a predominantly academic background have no relevant vocational experience. "
There were examples of work placements being organised through education and business partnership schemes, the report said, but "these opportunities are too few, too brief and are taken up by only a small number of teachers.
"Colleges need to encourage and enable teachers to keep up to date with modern trends and developments in their particular fields."
The report says colleges have concentrated staff development funds on training lecturers to assess students for NVQs and other work-based awards.
But, it says, "colleges have spent less on updating the subject expertise of staff, providing them with industrial experience and promoting curriculum development."
The report, based on a 1995 survey of lecturers, will reopen the debate about teaching standards in colleges. The FE staff development forum, a coalition of staff and representative bodies, is currently developing a new set of teaching qualifications for FE staff, something demanded by senior Labour figures before the general election.
The report, however, does point out that inspectors usually describe lecturers as adequately qualified when they visit individual colleges.
Inspectors said: "No college inspected has been awarded less than a grade three (the lowest grade is five) for staffing and 90 per cent of colleges have been graded one or two, indicating that the strengths of staffing arrangements clearly outweigh weaknesses. This assessment takes other factors, such as industrial experience and the number of teachers employed, into account alongside paper qualifications."
The report added: "The low level of teachers' qualifications has rarely been identified as a cause of poor practice in teaching and learning. However, there are examples of poor lessons where teachers had low expectations of students or teaching was dull and uninspiring."
The report also criticises the standards and relevance of some vocational qualifications - for years a key complaint of critics.
Inspectors said: "The Charter for Further Education tells students that they 'have a right to expect that all qualifications the college offers are soundly based and have value outside the college itself.' . . . this expectation is not always fulfilled . . . the comparability of qualifications offered by some of the smaller awarding bodies is difficult to determine and some qualifications have little national currency."