I haven' met anyone who understands Pers in 20 years. Pers is not a funded pension. 
It is leveraged financial scheme.  The actuary is not God. 8% is without  facts.  It is a fantasy.
It is for the airhead elite and other harlequin readers. The true Unfunded liability is over 80 Billion.  So, they borrow the money nitwit.  Interest compounds  exponentially. Do the math.