Guys my maths are based in old VGC numbers (where they tracked more countries eg. the http://web.archive.org/web/20120119110416/http://www.vgchartz.com/hwtable.php) plus official numbers.
Australia has a lifetime sales of ~1.4m for 360 back in 2011... I think 3% today (~2.4m) is low to AU + NZ today.
I used old or low numbers to reach these 87%... that's why I think close to 90% is more reasonable.