"the problem is in the middle - among the third, fourth and fifth quintiles of income earners"
Curious. How did the fifth quintile eg the bottom 20% become a problem of the middle?
Research from the Tax Office shows the top quintile are net payers into the tax system and the 80% remaining are net takers.
And the solution from Labor is to take more from the top 20%. It is not a very sustainable option.
