Don't have a good way to figure it out for an arbitrary year.
The year's offset is 0 when jan 1st is a thursday (since the whole system is based on determining the day's offset wrt a thursday), i.e. 1998, 2004, 2009, 2015, and increase every year by 1 and every mod 4=0 year by another 1. If you remember the offsets for a few years, then it's quite straightforward to get the offset for a nearby one.
But i can't quickly determine the offset of an arbitrary distant year.
The year's offset is 0 when jan 1st is a thursday (since the whole system is based on determining the day's offset wrt a thursday), i.e. 1998, 2004, 2009, 2015, and increase every year by 1 and every mod 4=0 year by another 1. If you remember the offsets for a few years, then it's quite straightforward to get the offset for a nearby one.
But i can't quickly determine the offset of an arbitrary distant year.