Note that the report focus on socially engineered malware which is actually a huge problem currently. This includes all those malicious links on twitter, facebook, instant messaging and so on. They are coming directly from your friends, so most people assume they are safe. If Internet Explorer 9 beta blocks 99% of those and Chrome only 3%, that makes a huge difference.
Just like the days of worms automatically spreading over the internet via remote exploits are quite much gone, the amount of drive-by download exploits is lowering too. However a well-crafted socially engineered attack will always work on people and as a bonus it works across all browsers and even on Mac OSX and Linux. That is, if browser isn't itself trying to prevent those, like Internet Explorer 9 is. With IE's sandboxing and this feature, IE9 is surely starting to look like a really secure browser for people to use. Now, if companies would just start updating their stuff and abandon IE6...