Here's the full breakdown:

1. Three words: 26 percent
2. Two words: 19 percent
3. Four words: 17 percent
4. One word 14 percent

These figure confirm a trend that users are increasingly using long queries, therefore SEOing should follow suit and be performed for 3 to 5 keywords. The survey doesn't distinguish between brand and non-brand keywords though, the likely result being that brand queries use less keywords than non-brand.

This is an opportunity to remind of the importance of the long tail principle, whereby few short queries generate 50% of the traffic and many long queries the other 50%. The latter driving a much more qualified audience onto the site.