MacBook Pro – Is 10% Battery Capacity Loss in 8 Months Normal?

Battery life depends greatly on use. 238 charge cycles in 5 months by most standards is pretty high. More importantly if your following the guidelines Apple has published for their battery use are you getting usage times that are in line with their estimates? Coconut battery isn't always accurate, its best to trust the built-in tools for diagnostic information.

You can also check System Information (Lion) or System Profiler (10.6) under power to get an idea of the stats on the battery. Double check to see what your Full Charge Capacity and the Charge Cycles are.

Any Apple Store or Authorized Service Provider can run diagnostics on the battery as stated by Wheat Williams. If it is faulty it's covered by your one year limited warranty.

Also check for run away processes you can check Activity Monitor, these could be draining the battery faster and driving up charge cycles. http://support.apple.com/kb/TS1473

It sounds like you've got a bad battery, no doubt, and should have it replaced, gratis. While this shouldn't be a problem, it won't hurt to have the most ammunition possible when you arrive at the store or have to place a call to Apple Care. Take a screenshot of the "Service Battery" menu icon (Shift + command + 3), and collect all the data you can (like the kind you've included in your question). I've had three defective batteries replaced by Apple, two of them close to the 300 cycle mark, which is what Apple guarantees 80% battery health to. The screenshots and data have been instrumental in getting a rapid, no questions asked replacement. Of course, if your battery is showing the health problems that it is after only six (!?!) cycles, then you've got a good shot at it anyway.
Good luck!