1. A method of deduplicating backed-up data, which comprises: creating a backup table at each of a plurality of backup clients, wherein each said backup table comprises a list of files and respective file types to be backed up; receiving at a backup server backup tables from said backup clients; merging at said backup server said received backup tables to form a merged backup table; sorting said merged backup table according to file type from a file type fielding a best deduplication ratio to a file type yielding a worst deduplication ratio to form a sorted backup table, wherein a deduplication ratio for an original file is calculated by dividing an amount of space that would be required to store said original file by an amount of space required to store a deduplicated version of said original file; requesting the files listed in said sorted backup table, in order, from said backup clients; deduplicating files received from said backup clients, in order, using deduplication parameters optimized according to file type, said deduplication parameters including a chunking technique, a hashing technique, and a hash collision resolution technique; calculating an average deduplication ratio for each deduplicated file type by dividing a sum of the individual deduplication ratios achieved for files of said each deduplicated file type by a number of the files of said each deduplicated file type; and updating the deduplication ratio for each deduplicated file type with said calculated average deduplication ratio.