Want to understand why the world is going through sovereign debt gyrations that threaten to plunge the global economy into a new crisis?

Tracy Alloway has snagged a fantastic chart from a new BIS report, which she calls "the most important chart in the world right now."

Basically, it looks at total issuance of AAA-rated credit by year. You can see there are twin peaks: First in 2005 and 2006, during the worst of the housing-related excess, when garbage was repackaged into AAA, and then following that AAA-rated issuance peaked again when governments bailed out the financial sector.

So now... well, you know what's going on these days.