I traced back to my past 5 years and i notice its different but within a range every year.
Yr 1 - increased by 216 (grade c)
Yr 2 - 346 (grade b)
Yr 3 - 462 (grade b, promotion)
Yr 4 - 234 (grade c+)
Yr 5 - ?? (Grade b)

I am anticipating an increase of around $300++