Long run interest rate projections & public finance

[Alex Lantsberg <alantsberg@xxxxxxxxx>]

PEN-pals...

I'm critiquing a report establishing development mitigation fees that are in
part based on long-term returns to a public investment annuity fund.  Can
anyone point me to a chart or table showing average annual effective yields
for a variety of financial instruments including US Treasuries, munis, and
high grade corporate bonds?  Also is the assumption of a 6.11% return in
perpetuity for a relatively conservative investment fund optimistic?

Thanks
Alex