How long did it take to render Sintel or Tears of Steel movie?

How long did it take to render 4k Sintel and Tears of Steel movie? What about 1080p? I know Blender Foundation team is dedicated in using only Blender as their video editor and compositor. I wonder how long did it actually taketo render their movies.

There are blog entries all about the render farm and their experience of 4K. It was long and slow.
http://mango.blender.org/