Sanderson is currently 68% done w/ the 3rd draft of "Oathbringer" (Stormlight 3). It should be out this fall
A 10 book series at the current pace would be:
2010: Way of the Kings
2014: Words of Radiance
2017: Oathbringer
2020: Stormlight 4
2023: Stormlight 5
2026: Stormlight 6
2029: Stormlight 7
2032: Stormlight 8
2035: Stormlight 9
2038: Stormlight 10