"10 or more people [...] as the result of a deliberate attack" seems to suggest that 10 assassinations in 2010 would probably not qualify - unless it was proved that they were all linked. My summary of the link is that there have been few terrorist attacks against Americans on American soil recently.
Agreed.
I would like to propose this as a thread for people to write in their predictions for the next year and the next decade, when practical with probabilities attached. I'll probably make some in the comments.