Complex sentence: The past decade has seen an extraordinary rise in the number of copublications with foreign partners, which represented 75--80% of all Zimbabwean publications in the Web of Science over 2008-2014.
Split into simpler sentences: The past decade has seen a steep rise in the number of copublications with foreign partners. These represented 75--80% of all Zimbabwean publications in the Web of Science over 2008-2014.