Alaska's funding level for its pension system—at 74% in 2006—is below the national average, but that is a major jump from the state's 64% funding level in 2005. Alaska is one of just a few states to have funded retiree health and other non-pension benefits as part of its pension system. Its long-term liability of $3.4 billion for retiree health benefits was 65% funded as of 2005. Alaska started pre-funding its retiree health costs in the 1970s and was one of only three states in 2006 to have set aside enough to cover more than 50% of its liability. Alaska is one of seven states in which neither teachers nor state employees participate in the U.S. Social Security system.