I suggest you apply a relative weights analysis, which takes into account collinearity issues. For more details have a look at the following publication:

Johnson, J. W. (2001). Determining the Relative Importance of Predictors in Multiple Regression: Practical Applications of Relative Weights. In F. Columbus (Ed.), Advances in Psychology Research, Vol. 5 (pp. 231–251). Huntington, NY: Nova Science.

This might help too.....

Tonidandel, S., & LeBreton, J. M. (2011). Relative importance analysis – A useful supplement to regression analyses. Journal of Business and Psychology, 26, 1–9. doi:10.1007/s10869-010- 9204-3

Thank you all for your responses, they are helpful