The 5k+ season ticket seats from last year are held until 3 July, so even if someone hasn't yet renewed, the seat will be showing as taken.
I think the club last noted sales at 4.5k a few days ago. Bear in mind we're approaching the extra payday that the club extended the renewal deadline for; I'd imagine we'll hit 5k imminently.
There were only couple of hundred season tickets left to be bought though, as the club have limited the number of season tickets to around 6/6.5k. Any that aren't renewed by 3 July will be back in the general sale on 4 July, so by then you'll be able to tell with more certainty.