This was the data collected by BOSTES regarding the performance band descriptors. It shows the proportion of students achieving b6,5 and 4 over the past years:
2014: 0.28% 7.93% 35.24%
2013: 0.41% 6.42% 27.13%
2012: 0.41% 6.42% 27.13%
2011: 0.16% 8.7% 29.96%
2010: 0.18% 4.13% 30.58%
2009: 0.2% 5.15% 30.7%
2008: 0.23% 5.72% 31.94%
Note that they made changes to the rubric in 2009. However, this data suggests that the likelihood of achieving a b5 isn't necessarily higher even though they changed the syllabus.
I think it depends on the proportion of kids that completely flunk out and don't make a legitimate attempt which can't be predicted
You can probably expect the b5 rate to be around 7-8%
