Rear shoulder room?

[Tom Kramer]

If someone has the time and a tape measure, would you kindly measure the "real world" shoulder room in the back seat (door-to-door)? I haven't had the time to stop at a dealer to do this and I'm determined to see if three car seats will fit back there.
I saw a beautiful H3 today- blue with chrome wheels- and it fueled my desire to get one.
Many thanks!