the vast majority(the vast majority (of something). used when you want to emphasize that something is true about almost all of a group of people or things: The vast majority of books on the subject are complete rubbish. LDOCE Alexander Demidov)
the vast, overwhelming majority(Explaining the objective, the statement continues: "It is hoped Cardiff City FC and its owners will accept that the vast, overwhelming majority of ... | The vast, overwhelming majority of American Christians–probably about 99 per cent–obey God almost perfectly, because they are so grateful for their salvation ... Alexander Demidov)