We aim to ensure staff satisfaction, which we monitor through our annual staff survey, and to minimise the voluntary turnover of staff. However, staff turnover has increased from 14% in 2005 to 16% in 2006. There are a variety of reasons that have been identified for this increase, including market conditions and workforce mix which can have a bearing on annual comparisons.
Higher levels of staff turnover are a concern to us, and our analysis indicates that their highest levels apply to professionals in the earlier stages of their careers. This is a normal pattern which is to be expected as they seek to develop their careers and explore opportunities. Professionals in the earlier stages of their careers generally mention career development and the quest for wider experience as motivating factors, and this aspect of their concern has been the focus of a number of our initiatives. By contrast, there remains relative stability amongst more senior and experienced staff where turnover remains relatively low. The charts below set out the length of service and age distribution of staff throughout the Group.
In Sweden, we have piloted an intranet site focused on career development, and in the UK a performance management programme has been launched which provides us with a tool for personal development to set and communicate performance expectations. Over the coming year it is planned to implement these developments more widely across the business. We believe that with the current growth and diversity of the Group, WSP is well positioned to create space and allow staff to develop their skills and talent.
This is just part of our retention strategy and we also aim to motivate and support staff through flexible and competitive remuneration packages. We seek to ensure a good work-life balance for our staff and, wherever appropriate, we enable job sharing and flexible hours. Seven per cent of our permanent staff work on a part-time basis.
In addition to the experience that staff gain through the variety of projects undertaken by WSP, they also undertake formal vocational training and benefit from our web-based training portal, WSP University, which continues to expand. This year, WSP University embarked upon an interactive e-learning programme to complement existing training. Investment in training has continued to rise and this year amounted to £9m (2005: £8m), including opportunity cost.
Our highly successful Taskforce continues to provide early career professionals with an opportunity to shape the future of the business, and this year they hosted their bi-annual conference in Stockholm, with 130 delegates from across the world focused on the theme of business growth.