The President may contribute up to 75 percent of the cost of hazard mitigation measures which the President has determined are cost-effective and which substantially reduce the risk of future damage, hardship, loss, or suffering in any area affected by a major disaster. Such measures shall be identified following the evaluation of natural hazards under section
of this title and shall be subject to approval by the President. Subject to section
of this title, the total of contributions under this section for a major disaster shall not exceed 15 percent for amounts not more than $2,000,000,000, 10 percent for amounts of more than $2,000,000,000 and not more than $10,000,000,000, and 7.5 percent on amounts of more than $10,000,000,000 and not more than $35,333,000,000 of the estimated aggregate amount of grants to be made (less any associated administrative costs) under this chapter with respect to the major disaster.