Lamentation was published in February 2009, Canticle in October 2009 and Antiphon in September 2010, with Requiem expected in mid-2011, so he's going at a fair old clip.

These are fairly short books though (350 pages, short for fantasy), so it's not quite as impressive as Erikson burning through a 1,200 page book every ten months or Dan Abnett publishing three 450-page novels a year.