Answer:
1 to 2 inches (3 to 5 centimeters) per year
Explanation:
It depends on what plates your talking about, but in general, they move apart anywhere from 1 to 2 inches (3 to 5 centimeters) per year.
Specifically, though, The Arctic Ridge has the slowest rate (less than 2.5 cm/yr), and the East Pacific Rise near Easter Island, in the South Pacific about 3,400 km west of Chile, has the fastest rate (more than 15 cm/yr).
