That test was a little tough for me considering it was fairly short. I ended up getting 64WPM with 93% accuracy. The errors I made and didn't pick up seemed to mainly be on spelling differences between UK English and American English. For instance, I typed "colors" instead of the "colours" that read in the passage. Just force of habit, I guess. Like Thantos said, a big part of doing well on these tests is knowing the word set.
To be honest, I did that test a second time and ended up with an Old English passage that I did horrible on; getting something like 48WPM with 85% accuracy. Every time it said something like "thy," I ended up typing "they" and having to correct it. This makes me commend our forum members who are not native English speakers getting good results on these tests. I'm sure if they never have, they'd find that they get much better results on a test in their native language.
... and since other have posted about how they type... I do not type properly. I don't use every finger... I'm not a two finger typist, though... I'd say I'm more of a seven finger typist. My index and middle fingers handle all of the letters and numbers while my pinkies handle the shifts and some punctutaion. My right thumb does most of the space work. My left thumb and two ring fingers do almost nothing... sometimes I'll catch myself actually using them in place of my pink, but not regularly. Basically, I have no consistency. Any given key can be touched by a few different fingers depending on where my hand placement is at the given time.