If you click through to the IBJ investigation it states the backdating ran from 1999 to 2013. I don't know why the BBC only reported up to 2005.
Picking on particular scandal to publicize is more like picking from large heaps of content in a collection, not anything unique or unusual at all.. just not widely known for real reasons...
Tax evasion is a game played by 100% of sophisticated players, to start IMHO