USSubCo is a United States C Corporation that is wholly owned by AwayCo, a company incorporated in country F$.$ Country F has a tax treaty with the United States similar to the United States Model Treaty. AwayCo produces doodads and earns $$600,000$ of income, all from the sale of those doodads to USSubCo. USSubCo owns valuable marketing intangibles, which make its resale of the doodads extremely profitable. During the current year, USSubCo earns income of $$20$ million that USSubCo distributes as a dividend to AwayCo, which is privately owned by $7$ unrelated residents of Mexico. After receiving the dividend, AwayCo pays $$7$ million of compensation $($which is reasonable, ordinary, and necessary$)$ to one of the Mexican individuals, who acts as AwayCo$$s COO.

What is the rate of the withholding tax on the dividend? Why?