So we know there are only 122 Vaults in the entire series and yes while the number could be expanded in the future, let's instead go with the idea that Bethesda will stick to that number.
That poses the question, canonically how many vaults have not been explored yet? The Vault Numbers are all over the place and I am very curious to know roughly how many Vaults are left to be made into future content? My estimate would be around 30 but I would love to know for sure.
Also as an added point. Could someone explain to me the reasoning behind the sporadic numbering system of each Vault? Is it the order of construction or something to do with the location?