Here's data from 1990 through June 2010 on Calper's performance vs. some common benchmarks:
|Avg. Ann Return|
Now, over this historical period interest rates declined from 8% to 3%, which added about 2% to the annual returns (asset prices rise when you decrease the discount rate). That isn't likely to repeat. At best rates will be stable, but probably they will increase. This will drag down not only their bond returns, but equity as well (bond and stock returns generally positively correlated). Thus, they are anticipating the same 5% return over inflation that occured with the one-time secular interest rate decline these managers experience over their working life (which tends to make one think it's simply a given).
Either someone invents cold fusion, the Mayan alien astronauts bring us all sorts of manna when they return in 2012, or we will monetize our debt to pay for all these off-balance sheet liabilities. I'm betting on the latter.