Minecraft Enchanting Calculator for Minecraft version 1.7 - http://www.minecraftenchantmentcalculator.com/

Output log:  (This output was calculated 10,000 times, but results may still vary)
Possible enchants for book at level 17...
Unbreaking II: 10.4%
Sharpness II: 10.2%
Protection II: 10.2%
Efficiency II: 10%
Power II: 10%
Knockback I: 5.3%
Projectile Protection III: 4.9%
Bane of Arthropods II: 4.9%
Smite II: 4.7%
Feather Falling III: 4.5%
Fire Protection II: 3.2%
Looting I: 2.3%
Punch I: 2.1%
Aqua Affinity I: 2%
Fire Aspect I: 2%
Fortune I: 2%
Respiration I: 1.9%
Blast Protection II: 1.8%
Fire Protection I: 1.7%
Silk Touch I: 1%
Lure I: 0.9%
Thorns I: 0.9%
Luck of the Sea I: 0.8%
Feather Falling II: 0.5%
Flame I: 0.2%
Respiration II: 0.1%
Infinity I: <0.1%
Efficiency III: <0.1%
Unbreaking III: <0.1%
Smite III: <0.1%
Bane of Arthropods III: <0.1%
Projectile Protection IV: <0.1%
Power III: <0.1%
Blast Protection III: <0.1%

You have a 19% chance of getting a 2nd enchant.
You have a 10.5% chance of getting a 3rd enchant.
You have a 6.25% chance of getting a 4th enchant.

You cannot get Fire, Blast, Projectile or regular Protection on the same piece of armour.