(You have to have a little patience - remember, we're all volunteers )
Anyway, it seems that for our SCJP 1.4 book most people get about the same score on the real exam. I'd say if you're getting 55-60% you're cutting it prertty close, personally I'd recommend a little more study. (This is different than the SCWCD book - in that case people tend to do much better on the real SCWCD exam.)
p.s. Most people find that threads, inner classes, and GC are the hardest topics - you might want to focus on those areas.
Eliminate fossil fuel subsidies. (If you're not on the edge, you're taking up too much room.)