"Average final compensation" means the average annual earnable compensation of any employee during his last five years of creditable service or, if he has had less than five years of creditable service, his average annual earnable compensation during his total creditable [...]

"Average final compensation" means the average annual earnable compensation of a teacher during the last five years of creditable service or, if he has had less than five years of creditable service, his average annual earnable compensation during his total creditable service [...]