ASX Total Return

Often I read something that quotes an average and they rarely show their source or calculation of the figure.

Recently I read
"even with the financial year we’ve just had the ASX is averaging just on 9% on a total returns basis over the last 15 years."
referring the the 15 year period from 30 Jun 2007 to 30 Jun 2022.

I looked at the XNT and the XJT (XJOA) and the return for the period is more like 6% than 9% based on:
XNT 30Jun22 = 73099.898
XNT 29Jun07 = 38386.76
=> (73099-38386)/38386/15 = 0.06

Am I missing something obvious? Is there some adjustment or grossing up of the 6% or is the quoted 9% total return just wrong?