From the amount reserved pursuant to section 629f(b)(3) of this title for any fiscal year, the Secretary shall allot to each Indian tribe with a plan approved under this subpart an amount that bears the same ratio to such reserved amount as the number of children in the Indian tribe bears to the total number of children in all Indian tribes with State plans so approved, as determined by the Secretary on the basis of the most current and reliable information available to the Secretary. If a consortium of Indian tribes submits a plan approved under this subpart, the Secretary shall allot to the consortium an amount equal to the sum of the allotments determined for each Indian tribe that is part of the consortium.