99% of humans in a particular specialization, sure. It's the 1% who become experts in that specialization who are able to advance the state of the art. But it's a different 1% for every area of expertise! Add it all up and you get a lot more than 1% of humans contributing to the sum of knowledge.

And of course, if you don't limit yourself to "advancing the state of the art at the far frontiers of human knowledge" but allow for ordinary people to make everyday contributions in their daily lives, you get even more. Sure, much of this knowledge may not be widespread (it may be locked up within private institutions) but its impact can still be felt throughout the economy.