Context: While the 90% figure is made-up, the premise is true in that most of human history has gone unrecorded. History is considered to have begun with the start of proto-writing (earliest being the Jiahu symbols in China circa 6600 BCE) to writing (3200 BCE), and thus the advent of recorded history.
If we could ever figure out FTL and create super-telescopes, I want them to point it at earth from 200,000 light years away and hit record.