I found this via the Huffington Post. And here' s the poll that they're all pointing to. It stacks all 100 senators by their individual approval/disapproval poll numbers. If you take a look waaaaaay down at the bottom of the list, you'll see our lil ricky - approval ratings at 39%, disapproval at 53%. I'll do the math for you. It's a difference of -14%.
Those are the worst numbers in the entire Senate.
According to these poll numbers, not only is Rick Santorum the least popular of them all, but he's also one of only three Senators (all Republicans, by the way) whose disapproval numbers are actually higher than their approval numbers.
Couldn't happen to a nicer creepy religious fanatic.