The course modulator should have told you on the first lesson! Sorry, it was about 7 months ago when I had my first lesson, but I am guessing that there wasn't a percentage. I was informed to focus on getting a pass, and not to be to worked up on getting a Pass A or Pass B.
Also, Keep in there Sparrow! I know how you feel at the moment!
Back to the CELTA course. They assess you through the lesson plans and how you teach in class. You will have to work hard on all aspects of English teaching (Teaching Grammar, listening, reading and speaking exercises) and really impress the assessors viewing each of your classes.
In a nut shell, I think you can learn and practise to be a good teacher, but the really great teachers stand out amongst the rest possibly due to other qualities (sense of humour, being approachable, loving their job and the students being able to see that the teacher loves his/her job) and I guess most importantly, the assessors seeing that the students have learnt something new in the your classes.
Good luck for the rest of the course Sparrow!