It was 76 years from Washington’s First Inaugural in 1789 to Lincoln’s Second Inaugural in 1865. It was 76 years from the surrender at Appomattox Courthouse in 1865 to the attack at Pearl Harbor in 1941.
Going backward, it was 76 years from the First Inaugural in 1789 to the Treaty of Utrecht in 1713, which settled one of the British-French colonial wars. And going 76 years back from Utrecht takes you to 1637, when the Virginia and Massachusetts Bay colonies were just getting organized.
As for our times, we are now 71 years away from Pearl Harbor. The current 76-year interval ends in December 2017.