Looking at that chart is a start, but I'm not sure how much stock I'd place in it because you have to wonder how people put in their numbers. I'm hoping most just put in their average on the tests they took during the last few weeks, but you just don't know.
Personally, I think with those scores in three weeks you can definitely improve a lot. My scores were about the same as yours 2 weeks ago and now I'm averaging about 80 on JQ+ and 86 on JWhiz. I'm hoping I'm ready because I take the exam on Tuesday
I'm starting to get real nervous.
The biggest thing that is messing me up is there are a lot of methods in the Collection classes and a lot of AWT constructors and methods and knowing all their signatures (especially return types can be a pain). I've done practice coding with all of these areas but not really enough as I probably should (so don't yell at me Valentin
For example in the Vector class add(Object o) returns boolean, yet add( int index, Object o) is void. Then in HashMap put(Object key, Object value) returns an Object. So here you have in your mind ok I know different ways to add Objects into a particular Collection but now I have to know the return type also. Despite how much coding I do, I'm bound to forget some return types. Most of the time when adding stuff into a Collection class on a daily basis I don't even check the return type. The point is, I still think asking these types of quesions on this type of exam does not really prove much. All the other stuff sure. I'll be really curious after the real exam, how obscure some of the methods they require you to know are- I'm hoping JQ+ and JWhiz through a couple odder ones in there to keep you on your toes. (However, I'm not so sure since these are often marked "Very Easy").
Overall, I think you are in good shape depending on how much time you have during the next 3 weeks. Good luck. If you have any questions let us know.