I don't know if this is typical but just as an example (seeing as you've had no other answers...)
I've got a 38K repayment mortgage. Over the 4 years I've had it, I've repaid c11K and the actual debt has only gone down by c3K. The rest has covered the interest.
It depends on the interest rate, the amount of the loan, the term of the loan, the interest calculation, any over or under payments made, the repayment type.
As whoever arranged your mortagge - they should supply you with this information.