A school tracks the total number of students enrolled each year. The school uses the change in the total number of students to estimate how many students have been enrolled in the school each year since 2000. If [math]t[/math] is the number of years after 2000, the total number of students, [math]f(t)[/math], can be estimated using the function [math]f(t) = 250(0.98)^t[/math]. How is the total number of students changing each year? Is the total number of students growing or decaying?