Investment returns for the Colorado Public Employees’ Retirement Association were 15.6 percent in 2013, the pension system reported Tuesday in its annual financial report.

The health of the pension system is important to Colorado teachers, all of whom are covered by PERA and who make up the majority of the system’s members. It’s also closely watched by school districts, which make millions of dollars in employer contributions each year.

PERA assumes an average 7.5 percent return over 30 years, so the 2013 report is good news.

The system had $43.7 billion in assets for its defined benefit plan at the end of 2013, an all-time high. PERA’s overall funded status increased to 64.2 percent in 2013, primarily because the $6 billion of investment income earned on its portfolio.

Despite a comprehensive overhaul law passed in 2010, PERA remains the focus of political controversy, with many Republican officials skeptical about the system’s long-term health without significant changes. Public employee groups and Democratic officials generally argue that the 2010 reforms need time to work. A 2014 law commissioned three studies to look further into PERA’s finances (see story).

Get more details on the system’s 2013 finances in this news release, and see the full report here.