Now I want to write a program to compute the monthly variance of historical events. I wonder how you'd build a list of historical events... Maybe it's a job for Wolfram Alpha.
Further more, I'll mention there is some crazy Russian who thinks our modern calendars (Gregorian) are an elaborate hoax. But, as I understand it, he had someway of applying algorithms to historically "significant" data points. (If you're actually interested, reply and I try and find his name again.)
...FWIW
Because I'd posit that the vast majority of the human world we experience today was shaped by chance events that nobody noticed.