Is this phrasing correct? "Each of the last two years..."
That's evenly divided. When I first read this, I did a double take, thinking it was wrong, but then I looked it up, and dictionary.com says this: "every one of two or more considered individually or one by one," and it gave the example "a hallway with a door at each end." This example is talking about a hallway with two ends, and "each" is used. I therefore think that "each of the last two years" is correct, though wordy. "Both years" would be more concise.