Is below long-term average but still above record low
Growing interest from institutional investors
On pace for another high in 2005, S&P says
Investors will be challenged to match returns of prior years
Aim is to prepare for upcoming Basel II accord
Index cover 901 corporate, government bond issues
Follows delay in filing of financials by American International Group
Index takes first step towards "full float adjustment"
Standard & Poor's report examines effect
Changes takes effect March 18