Humans are pattern-seeking animals. A good thing: that's how we got to be where we are.
But I think this particular thing is likely a matter of people dying near the end of the year. You always see the obituary column of the paper get very full around the end of December, as those who are already in bad shape try (maybe subconsciously) to make it past that milestone. Some do, most don't.
make it to the end of the year? i think they try to make it to the end of the week since you always see the obituary column of the paper full on sundays.