round() function wrong?

Hi All,
i'm running Postgresql 2.2x, so i am not quitse sure wether the bug i am reporting is already fixed
in newer versions or not.

In my version 
select round(2.5); returns 2;
select round(2.5000001) returns 3;

refering to my math professor thats wrong, at least in germany.
select round(2.5); should return 3

regards


jochen