Pollsters ask a fair number of questions about terrorism, but they relatively rarely ask people if they are personally frightened of a terrorist attack.
One exception is Gallup, which every year or two asks Americans if they worry that they or a family member will be victimized by terrorism. The results show that fear of terrorism spiked after 9/11, then settled down, then faded further when the financial crisis took center stage, and then faded even further once Osama bin Laden was killed. But over the past two years, personal fear of terrorism has surged, and in its June 2015 survey Gallup found the highest level of fear since October 2001:
Note that this was coming well before the Paris attack.
And it possibly explains why the political response to Paris has been so strong. A major terrorist attack in a European city would be a big news story under any circumstances, but previous attacks in places like London and Madrid (11-M was actually deadlier than the Paris shootings) didn't spark much of an emotional response in specifically American terms. But Paris splashed into the headlines and cable news channels at a time when Americans were already feeling a level of anxiety about terrorism that was higher than what we saw during the main war on terror years.