In terms of funding ratios for its various pension funds, California is hardly among the worst of states. But that could change easily, and uncertainty accounts for its inclusion here. A 2010 study by Stanford University found that between June 2008 and June 2009 CalPERS, CalSTRS and UCRS1, three public pension funds covering 2.6 million Californians, lost a combined $109.7 billion in portfolio value and, at that time, were underfunded by nearly a half-trillion dollars. A more recent study by the the Stanford Institute for Economic Policy Research found that none of the state's public pensions are at the recommended 80% funding level. Not only are its pension funds a financial drain; the health care benefits offered to retired public employees are adding to the economic stress. A report in February by state Controller John Chiang showed that the 30-year cost of providing health and dental benefits for state retirees is $62.1 billion. The unfunded obligation as of June 30 grew $2.2 billion from the $59.9 billion obligation identified as of June 30, 2010. While state pensions are pre-funded, allowing investment returns to reduce liabilities, California pays for retiree health benefits on a "pay-as-you-go" basis, or the minimum amount needed to fund the costs as they are due. Pre-funding benefits, he says, could reduce that liability by as much as one-third.