By Theodore Cangero, includes "At the state level, public pension funds bear significant stress. The gap between the benefits promised to workers and state pension fund assets was $1.1 trillion in 2015: a 17 percent increase from 2014. The gap is known as the net state pension fund liability. State pension funds were well-funded until the early 2000s, but in 2001, the net state pension fund liability began to increase."