I believe zoom levels follow Nikon's editing software. So it would look like this:
300% 200% 100% 66% 50% 33% 25% 16% 12% 8.3% 6.25% 5% <---- Being full image review with no zooming.
At least this is how it seems to scale playing with the camera and Capture NX2. Now I have my F2 setting for playback mode center button set for low magnification. So when reviewing, I tap the center control button and it brings me to the 50% zoom setting. Medium brings you too 100% and high brings you to 200% setting.