It took ?

It took = ?

Context:
Feynman speculated that people looking back from the year 2000 would wonder why it took till 1960 before we began to explore this "room at the bottom" - what we now know as the nanoscale. Late start or not, the progress in miniaturising information storage in the decades since has been stunning. Today, the smallest feature that can store a bit of information is some 40 nanometres across in commercial flash devices. The first flash chips capable of storing 64 gigabits of information were shipped just a couple of months ago.

Full context:
http://www.newscientist.com/article/mg20427370.600-five-ways-to-revolutionise-computer-memory.html