As per Section 26 of the Income Tax Act, in case of property jointly owned the joint owners
The tax benefits for interest and repayment of principal amount of home loan can be claimed only if one is a joint owner as well as a co-borrower servicing the home loan.
As per Section 26 of the Income Tax Act, in case of property jointly owned the joint owners shall be treated as owner of their share in the property and will be taxed separately for such share.
Since the property is jointly owned by you (the husband) and your wife, both of you are entitled to claim the benefit of interest under Section 24 as well as in respect of repayment of principal amount of home loan under Section 80C provided both are servicing the home loan.As far as your question about the ratio in which the same can be claimed the answer would depend on the ratio in which both of you are servicing the home loan which need not necessarily be in the same ratio for both.
In case only one of the joint borrowers is servicing the home loan, he can claim the benefits for such repayment in his own income tax return fully without other co-borrower being able to claim any benefit.So the ratio, in which the tax benefits of home loan can be claimed, need not necessarily be the same as the respective share of joint borrower in the ownership of the house.