Stats - countries

Every time I look at my stats the pictures changes (yes, ok don't go all anal on me here, I know stats change with time but can somebody please tell me what period the stats show?).

Anyway, am particularly impressed about having visitors from these countries: Unknown (where is this?), Brunei Darussalam (didn't know the correct country name here, thought it was Brunei only - isn't that the country with the sultan who rules the country as a dictator and has lotsa and lotsa money?) and Uruguay (far far away in South America if I'm not mistaken).