Many outside observers believe that European nations buy the greatest number of Montgomery Export's products, but Vietnam is unbelievably the single greatest consumer of these products.
Many outside observers believe that European nations buy the greatest number of Montgomery Export's products, but it is Vietnam that is the single greatest consumer of these products.
Many outside observers believe that European nations buy the greatest number of Montgomery Export's products, but Vietnam is unbelievably the single greatest consumer of these products.
Many outside observers believe that European nations buy the greatest number of Montgomery Export's products, but it is Vietnam that is the single greatest consumer of these products.
The structure "it is A that does X" is appropriate for dramatic emphasis, especially emphasis contrary to expectation. The adverb "unbelievably" is not appropriate to modify the performance of an action in which people other than the performer do not believe.