Animation position is different in each frame

Hi, I'm having some issues getting my animation to "stick" to the floor of my scene. I'm trying to "grow" my sprite. As an example, I have a rectangle starting off small and progressively getting larger with each frame of my animation.

Here is my simple sprite sheet



But when I import into Unity, slice it up, and create my animation, I end up getting this:

https://dl.dropboxusercontent.com/u/10250170/animation_alignment/animation_alignment.html

I don't understand why each frame is in a different position.

Does this have to do with Root Transform Position?

Any ideas?

Thanks.

 

Fixed. Had to set pivot to bottom when slicing up the sprite sheet.