DataSafe 40GB backup takes 2 days - Help with Math!

I've got highspeed wireless through cable company at home... never noticed abnormally slow upload speeds doing email, but then again not attaching massive amounts of files. But my first DataSafe backup ran for 2 days and still just halfway done - about 40 gig worth of files backing up. Is this normal for first time backup? Are subsequent ones significantly less because they only backup changes? Or might there be something peculiar going on with my upload speeds? Or my account? Is there a way to check what speed my files are uploading at so I can then do some math and see if the long backup makes sense?

Any help and/or suggestions greatly appreciated. Thanks!