He began writing the flashbacks on the 15th of June, so it's not 1% per day. It's pretty close to 12% per month though, which would mean that he gets the 1st draft done in February 2016. Of course, he might speed up his writing. I've been following his updates all the time and his speed has gone slightly up from what it was last month. Also, he once said in an interview that he writes 8 pages a day, and when he made the update of Dalinar's flashback being written he'd written 183 pages (55 000 words) which is "only" 5,7 pages a day.
And it's my first post! I've been a member for a while but apparently haven't posted before.