It's a bit difficult to pin down his common rate however the last two chapters that Murata has drawn have both been almost 60 pages and have taken about 3 weeks each to produce.
So currently he's matching actual weekly mag releases on average page count per week. Impressive considering he has little obligation to do so.
Murata/One have crazy work ethic. The only other mangaka I can think of that works as feverishly is Hiro Mashima.