for making payments to States, territories, and Tribal governments for any purpose (including payments made under section 601 of the Social Security Act), of which: (1) $10,000,000,000 shall be for making payments to the District of Columbia, Commonwealth of Puerto Rico, United States Virgin Islands, Guam, Commonwealth of the Northern Mariana Islands, and American Samoa: Provided , That of the amount made available in this paragraph, half shall be allocated equally among each entity specified in this paragraph, and half shall be allocated as an additional amount to each such entity in an amount which bears the same proportion to half of the total amount provided under this paragraph as the relative population of each such entity bears to the total population of all such entities