Well, arc's running on top of MzScheme, so it's likely to be a bit slower. Also, Stalin in the left column is a Scheme implementation, albeit one that is very restrictive for sake of raw speed.

Also, it's worth noting that the features in a language that make large systems' codebases manageable (such as good module systems) are different from the features that allow you to pare down small scripts further. It's hard to show features supporting conciseness-in-the-large in a one page benchmark, so IMHO the latter is often greatly overemphasized. Being able to knock 2 lines off 20 is often just a parlor trick, though, while 50kloc off of 200kloc can mean life or death for a project. The programming world would be a happier place if the size of every legacy C++ / Java codebase were cut by a double-digit percentage.