The California teacher pension system faces a $19.6 billion funding gap over the next three decades, despite three years of strong investment returns, according to a new report.

That means teachers, school districts and the state will need to boost contributions to the nation's second-largest public pension system, the actuarial consulting firm Milliman reported.

Milliman projected the fund needs a 3.3 percent boost in annual pension contributions to end the deficit. Currently, school districts pay 8.25 percent of payroll toward teacher pensions, while the state pays 2 percent and teachers contribute 8 percent of their pay.

The California State Teachers Retirement System (CSTRS) is the nation's second-largest public pension system.