I want to know the answer to the following question:
What percentage of Imperial's staff was classified as world leading in 2008?
All the background I'm provided with is that "The 2008 Research Assessment Exercise also showed five subjects – Pure Mathematics, Epidemiology and Public Health, Chemical Engineering, Civil Engineering, and Mechanical, Aeronautical and Manufacturing Engineering – were assessed to be the best[clarification needed] in terms of the proportion of internationally recognised research quality.". Is that enough to answer the question?