Cool Calendar Stuff

In honor of החדש הזה לכם:

When displaying a monthly calendar (using the non-Jewish months), a month will usually span 5 or 6 weeks, or rows in the calendar display.
Very few times will it display only 4 rows. This could only happen in February in a non-leap year, when it only has 28 days.
The pattern of year intervals when this happens is 6,11,11,6,11,11,etc.

It turns out that 2009 is one of those years.

So, here are the years that this happens on:

1981
1987
1998
2009
2015
2026
2037
2043
2054
2065
2071
2082
2093
2099

I thought this was interesting, but if you're asking "Who cares?", here's something that should interest you more:

Gilui's book on Birkat Hahama