Ship much art?
I use FedEx Ground a lot and admit to being slightly oblivious to all the charges and where they come from. Through a partnership program that I belong to (through a publishing organization), I learned of the enormous increases in shipping rates for 2009.
They say an average of 5.9%, but that's just an average. In some zones, it's much more.
With DHL no longer doing business in the US, sometimes our only options for larger shipments are FedEx and UPS. Here are the details about the rate increases from my partnership program, which seem as though they'll be applicable to you as well.