SACRAMENTO The leading Democratic plans for healthcare reform would be funded by requiring all California businesses to pay at least 7.5 percent of their payroll costs for employee health expenses.

That number and other financial data, determined by computer modeling conducted by an MIT healthcare economist, were released by Democratic leaders Tuesday, filling out the details of reform proposals making their way through the Legislature.

"These numbers show that healthcare reform is achievable and affordable," said Assembly Speaker Fabian Nuñez, D-Los Angeles.

Documents released by Nuñez's office point out that a recent Rand Corp. study determined that businesses that now provide health insurance to workers pay on average 13.8 percent of their payroll to provide the benefit.

Nuñez and Senate President Pro Tem Don Perata, D-Oakland, are each sponsoring healthcare reform bills based largely on expanding coverage through employer mandates, but Tuesday was the first time that the costs were detailed.

Although there are significant differences between the two plans, each would establish a state purchasing pool that would take contributions from employers and purchase health insurance policies for their workers. In those cases, employees would be required to pay $51 to $112 a month in premiums, depending on their incomes.

Companies also could choose to provide insurance to employees on their own, as most large- and medium-sized businesses do now.

Plans differ by $2.6 billion

The Nuñez plan would cost $8.3 billion and the Perata plan $10.9 billion. In each case, contributions from employers would cover slightly less than 60 percent of the costs, individual contributions from workers would cover about a third, and increased federal funding would cover the rest.

Each plan would expand coverage to about 3.4 million people, or roughly 70 percent of those who are now without insurance.

One key difference is that Nuñez's proposal would exempt businesses that have been operating less than three years and those with a payroll of less than $100,000. Both would exempt the self-employed.

The release of detailed plans is expected to intensify negotiations with Gov. Arnold Schwarzenegger, who in January unveiled his universal healthcare proposal that would require businesses to either provide insurance to workers or pay a fee equal to 4 percent of their payroll. Schwarzenegger's plan would cover nearly 1 million more people, in part because it includes a mandate that everyone have insurance.

With the cost figures now included, advocates for universal healthcare said the momentum for action has increased.

"For the first time, it's beginning to look real," said Art Pulaski, executive secretary of the California Labor Federation. "It takes us one step closer in a very big way toward universal healthcare."

'This can pencil out'

Anthony Wright, executive director of the advocacy group Health Access, agreed.

"The numbers show that major health coverage expansion is achievable that this can pencil out," he said. "The numbers make the conversation real."

Employer groups, which have been steadfastly opposed to employer mandates, said the numbers reinforce what they've been saying all along that businesses can't afford it.

"This is a healthcare tax on small businesses in low-wage industries that can't afford to purchase healthcare coverage," California Chamber of Commerce President Allan Zaremberg said. "If some employers and their employees can't afford to purchase health coverage today, they won't be able to afford to pay a 7.5 percent healthcare tax tomorrow."

Michael Shaw and the National Federation of Independent Businesses said none of the proposals would make health insurance more affordable, which he views as the key issue. Instead, he argued, a mandate on small businesses would hurt the economy, depress wages and dampen job growth.

"What incentives do insurance companies have to control their costs when everybody has to buy their product?" he asked.