Another way to think of it is that with the work done to this point, 71% of the time you'd have found a block already.

Of course that also means, 39% of the time blocks will take at least this much time or longer. The median is around 63%. Half of all blocks should be found below that, half above that.

And it stinks but long-term on average, 1 out of every 100 blocks will take 99% CDF of time to finish. Those are painful. But you are equally likely to land a 1% CDF fast block.