“The rule I have been taught and apply in such situations is that both are correct but have different meaning.” “What you want to convey to the recipient in regard to the relation between the element in the set (in this case – the year).” “Consider the following sentences. How would you describe them?” “big and tall a concept of store.” “What are the elements in the \”Big and Tall\” category of the English phrase \”long and thin\”?” “In the first, I regard both as a compound and refer to its joined properties.” “In the second, I treat both as separate elements in a set, referring to the individual properties of each.” “Considering all the major cities in the USA, which all have the same population.” “Compare the United States and large cities. c) Why?” “Both are correct and mean the same thing.” “Why could you substitute a large city for the capitol?” “The United States does have a capitol, unlike other countries.” “U.S. has large statesmanship. (National Capitals)” “So, the years have something, if you intend to regard them as individual elements that just happen to belong to a common set, whereas the years has something, if you mean to treat them as a whole that happens to consists of parts, the existence of which is of low relevance in the current context.”