Moreover, lower interest rates on their new issuance have resulted in the average duration of their debt rising by even more. The first two panels show that is true of most sovereigns. The Australian governments, Commonwealth and State, have proceeded along this path.
The Australian Office of Financial Management (AOFM) has significantly extended the curve in Australia, by issuing out to a 30-year 12 / 14  BIS central bankers' speeches  bond. A number of bonds have been issued well beyond the 10-year maturity, which was the standard end of the yield curve for a number of years.