The death toll of all these is fourteen: thirteen at Ft. Hood and one in Little Rock. I think it's fair to add to this the 2002 incident at Los Angeles Airport where a lone gunman killed two people at the El Al ticket counter, so that's sixteen deaths in the U.S. to terrorism in the past ten years.
Given the credible estimate that we've spent $1 trillion on anti-terrorism security (this does not include our many foreign wars), that's $62.5 billion per life lost.
Conspicuous omissions:
July 4, 2002: lone wolf attack on El Al counter at LAX. Two killed, four wounded. Since the shooter was also killed, there was no arrest.
It may be that the measures are extremely effective and that terrorism is actively prevented every day, but we just don't hear about the successes. It might also be the case of having a banana in your ear to keep away alligators.
"Why do you have that banana in your ear?"
"To keep away the alligators."
"But there are no alligators here."
"See! It's working!"
July 28, 2006: lone wolf attack on Seattle Jewish Federation. One killed, five wounded. The shooter was convicted in a state court.
Maybe these weren't considered "cases of terrorism" because there weren't federal criminal charges brought in response to either incident. Shooting a military recruiter is a federal crime; shooting a Jewish civilian is a state crime.