[Lexander]

Admittedly, I was just being picky, but when somebody takes into account leap year, they are trying for an exact calculation. The problem is that the exact calculation makes an assumption that is convenient, but not true, so exact calculations are a bit meaningless anyhow.

[BruceZ has pointed out that in fact he was not going for an exact calculation, which is pretty obvious once I see that nice little symbol for approximation. My bad).