I'm not sure there are such statistics. Read about the other ranchers who passed and wrote about their exam. Generally, you can expect a lot of EL and Custom Tags. But you should know everything taught in your book anyway. Relying on statistics is not a solution.
i wonder how such question came to tyour mind. is the WCD exam like the engineering exam, where in each chapter has e some aprroximate number of questions to be answered upon? things that you will learn in WCD preparations, will be actually used by you in job. so its rather a LEARN & APPLY process rather than LEARN & PASS proccess.
so try to read whatever you can.
SCJP 1.4 - 95% [ My Story ] - SCWCD 1.4 - 91% [ My Story ] Performance is a compulsion, not a option, if my existence is to be justified.