According to my calculations I'm just under 70% complete. I looked back and I started this back in December 2013 so I think its progressing on target. In the wake of what happened to Osgood in Death in Heaven, I've been using it as anger management to get over the loss* of her character.
*Well, we all know she had a Zygon clone and we don't know where she is. And we're not sure if the thing Missy used on her is a full TCE or a miniaturization one, and well, this is science fiction so who knows, she may come back for no other reason than Moffat decides to bring her back.