Due to the distributed nature of the pool system we don’t know exactly; but based on some sample measurements we estimate that the overall pool system on average handles somewhere between 40 and 120 thousand NTP requests per second.
If we assume it’s 50,000 a second, that makes a bit over 4300 million requests a day!
In a year that’s about 1500 trillion (american) / billion (other countries) requests a day. (1576800000000, if I’m counting the zeroes right).
That’s a lot of accurate time distributed; and yet triains, planes and meetings run late. :-)