It all depends on what assumptions you want to plug into a model.
As I argued previously the Portfolio Investment Entity (PIE) tax structure has some pretty good benefits for long-term savers - particularly the capital gains tax exemption for Australasian shares.
Based on the Financial Markets Authority (FMA) 2013 KiwiSaver report, the aggregate KiwiSaver PIE tax collected over that financial year equated to about 8.8 per cent of total investment returns.
In the booklet explaining its position, the FSC refers to "independent polling" showing 79 per cent of New Zealanders "want lower taxes on their savings".
But that's the easy question: the only surprising thing about this result is that 21 per cent didn't know, didn't care or actively opposed (just two per cent) lower taxes.
When it asked whether 'lowering taxes on savings would be better for savers and New Zealand longer term', the FSC survey was more equivocal: just over 51 per cent backed this proposition.
As the FSC points out this constitutes a "majority", albeit a slim one (that could be downgraded to a slim minority under the survey's +/- 2.1 per cent margin of error).
Let's call it 50/50.