The 2003 will be of about the record size as it seems, and the predictions are quite reliable. So, the answer is “yes, it can fluctuate that much”.
Something that usually is used against environmentalists, as some (other) fluctuations are normal, then the effect could be “just fluctuations”. The other side of the medal is never heard (not even by environmentalists): the same fluctuations could be “favoring” us, and the real man-made effect is much worse….