Five months after unveiling a sweeping plan to lower health insurance costs for middle-class Californians, Gov. Gavin Newsom now must sell the politically unpopular part of his proposal — hefty fines on those who do not have medical coverage.

The premiums state workers and retired public employees pay for CalPERS health insurance are projected to go up 7.2 percent on average next year, with premiums for specific plans increasing as much as 24 percent, according to preliminary estimates published Tuesday.

A new analysis of financial data from general acute care hospitals in California reveals that private insurers paid, on average, 209 percent more than what Medicare paid for similar services in 2015 and 2016.

While total expenses for prescription drugs are significantly larger for private insurance companies than for Medicaid or Medicare Part D, people with private insurance are still paying less out-of-pocket expenses over the course of the year, according to a recent analysis of Medicare Part D, Medicaid and private plans.

A half-dozen presidential candidates back “Medicare for All,” a proposal that would put the government in charge of most health benefits. But some of the Democrats they’re courting aren’t sure that the nation’s health care system should be overhauled so dramatically.

The health insurance inflation rate hit a five-year peak in April, possibly because managed care is rising.