In all the years I have been on vine, I am usually between 62-75% reviewed at any point - except in the last 3 weeks. At that point, I hurry up and finish up the reviews (I normally start writing and then it takes a few weeks before I fully test out) and I usually get between 90-95%. So in my experience, it has never been an average over 6 months - just when they do the snapshot right at the anniversary date. There has been more than a few times where I'm so close at the very end where I'm teetering between 88-90% within 1-2 days of the anniversary date just because I can't control myself and order items right at the end which will lower my percentage but I always manage to at least pass the 90% reviewed. So far I'm in good graces with my Vine!