Senior House Democrats have settled on a proposal to cover a significant portion of the cost to overhaul the nation's healthcare system by raising income taxes on the wealthiest Americans. House Ways and Means Committee Chairman Charles B. Rangel (D-N.Y.) said that the plan could generate as much as $540 billion over 10 years. Married taxpayers earning more than $350,000 a year in adjusted gross income and single filers making more than $280,000 a year would pay a surtax of at least 1%.