Progressives in California’s Democratic-dominated state Legislature have long called for a universal health care system to replace the one that mostly relies on private insurance companies. But their plans have often stalled over questions about how to pay for it in a state with nearly 40 million residents.

Assemblyman Ash Kalra proposed an amendment to the state Constitution that would impose an annual tax of 2.3% on businesses that have at least $2 million in annual revenue, plus a 1.25% tax on payroll for companies with at least 50 employees and a 1% tax for those employers who pay employees at least $49,900.

The plan also includes a series of tax hikes on wealthier people, starting with a 0.5% levy on the income of people who make at least $149,509 per year and ending at a 2.5% income tax for people who make more than $2.48 million per year. The California Taxpayers Association, which opposes the bill, says the plan would increase tax collections by $163 billion per year.