A fresh annual survey of the nation's public pension plans released Thursday revealed that government employee retirement funds plunged in value by a stunning 24 percent in 2009, before recovering many of those losses last year. The snapshot of the nation's retirement savings underscores how the financial crisis and the Great Recession combined to assail national fortunes, imperiling future generations of retirees.In the fiscal year ending June 30, 2009, state retirement systems lost nearly a quarter of their value, or $641.3 billion, according to new data released Thursday by the U.S.