"Only 10% of dry matter is produced by land plants while 90% of it is formed in oceans."

Explain the meaning of this sentence Experts....

Dear student,According to older estimates only 10% (17 billion tonnes) of dry matter is produced by land plants while 90% of it is formed in oceans. The present estimates put the productivity of land plants to be 68% of the total.By this statement they mean production by plants per year is 10% of total produce while 90% of total produce is from oceans.But now it is 68% from land plants.Regards.