Injured Spouse Claim

I recently filed an injured spouse claim because our refund was intercepted for some arrearages on my husband's child support. Does anyone know the formula the IRS uses to determine the portion of the refund that gets sent to the injured spouse? I know it is based on what each spouse made and paid in, but I would like to know exactly how they determine what my share will be from the info I had to provide on the claim form.

There is a worksheet for determining the separate tax liability of spouses in Publication 971, INNOCENT SPOUSE RELIEF (AND SEPARATION OF LIABILITY AND EQUITABLE RELIEF), which you can download for free at the IRS site at: http://www.irs.ustreas.gov/forms_pubs/index.html