I have no idea why any floodgate should open in 2017? It should already have started.
I suspect you know this but for those that don't I think what has happened is a significant number of the over 55s left ( voluntarily or forced due medicals etc)
between the ages of 55-65, there wasn't the step change in the retirement rate last Autumn that some were expecting or even hoping for....Unless there's a massive change, for example in something like Pension Provison/legislation, or a sudden offer of Paid, voluntary retirement, I suspect the current rate of retirements will probably be typical for some time to come.