Hi Kiwi,
I was :-)
We do not have four group ( 2 V and 2 placebo), just two. We could say that the event rate was lower till May 2013, but increasing till the end of the enrollment phase (later in 2015) - nothing less, nothing more. After full enrollment the event rate will be the weighted average of the '2012-13' and the 'after 2013' population (app. 5.2k and 2.8k respectively).
btw: maybe the lower was 5,2% and higher now ...