Rising tide of laptop battery recalls

With Dell's recall of more than 4 million laptop batteries today, I started to wonder if we're seeing more laptop battery recalls than usual. Here's a time line of all the battery recalls from the U.S. Consumer Product Safety Commission (CPSC) for the past five years. There were no laptop battery recalls in 2002 or 2003 in the United States.

• August 2006: Dell recalls more than 4 million Sony batteries.
• July 2006: Apple announces 15-inch MacBook Pro battery exchange program. The Consumer Product Safety Commission has not issued a formal recall notice for this product.
• April 2006: HP recalls 15,700 laptop batteries for overheating.
• December 2005: Dell recalls 22,000 notebook batteries.
• October 2005: HP recalls 135,000 laptop batteries.
• May 2005: Apple recalls 128,000 iBook and PowerBook batteries.
• August 2004: Apple recalls 28,000 PowerBook computer batteries.

As you can see, it's not just me. There definitely seems to be an increase in frequency. What's causing it is a whole different question.