It's hard to compare with 0, unfortunately. Also, if someone's goal was to inflict maximal damage on the US, striking whenever there was less effort put into s

It's hard to compare with 0, unfortunately. Also, if someone's goal was to inflict maximal damage on the US, striking whenever there was less effort put into security would be exactly what you'd want to do - regardless of whether the change actually affected security. So an increase in attacks might not actually reflect an increased vulnerability to attack, if that makes any sense.