In the recent period, the unemployment rate also fluctuated between roughly 4 percent and 10 percent, but inflation has been relatively tame, averaging 1.7 percent and never declining below 1 percent or rising to 2.5 percent. Even during the financial crisis, core inflation barely budged.
As a thought experiment, look at the right panel and imagine that you could see only the red line (inflation), and not the blue line (unemployment). Nothing in the red line hints at a major economic event, let alone the immense upheaval around the time of the global financial crisis.