Could I Get Criticism on Heroic Tier Centaurs

[bjacks14]

I've created a handful of heroic tier centaurs (specifically Centaur Archers for level 1 through 10) for my Guild Wars 2 campaign setting here (http://www.giantitp.com/forums/showthread.php?t=314790). As this is my first try with developing creatures from scratch, could I get some criticism from the more experienced? I'm just looking to see how balanced these creatures would be for their respective levels and how it looks in general. All the statistics are in a pretty pdf. Thanks for the help folks! Here's the file:

http://www.mediafire.com/view/80fdcwplpbdi431/Monsters.pdf