Count the corks

One of my friends is a very keen wine drinker, and as it so happens myself and other friends help drain his supplies on a regular basis.

The corks each year go into a jar, and we try and estimate how many there are.

The picture below show the last three years. The middle jar is the latest 12 months – 03/04. The one on the left covered 02/03 and has 393 corks. On the right is 01/02 with 325 corks.

Entries are welcome to guess how many are in the middle jar.