You get a sense that your vaccination target for going, and planning on staying, lockdown-free is between 50 - 70 percent of the adult population fully vaccinated. You'd probably want to err towards the high side of that range.
My guesstimate, which I hope is wrong, is that Scotty will announce 80% as the magic number, hopefully with some nuance around essential workers and the aged and otherwise particularly vulnerable.
Better to aim for 80% and open up at e.g. 75% in the light of the then-prevailing circumstances, than aim for 70% and realise that in the light of the then-prevailing circumstances it would not be prudent to open up at that number.
And along the way the ongoing consideration of and disquiet over the ever-increasing real costs paid versus the value of the projected lives saved may result in the target - whatever it is - being mugged by reality.