The surplus in the EI account in 2006-07 was roughly $1 billion, if one excludes interest earnings on the account. That reflects significantly stronger labour markets than were expected at the time the rate was set. For example, in September 2006, which was the basis for the 2007 EI rate projections, the forecast unemployment rate at the time for 2007 was 6.8%. It turned out to be 6.3%.
On November 20th, 2007. See this statement in context.