hairy_hen said:

It doesn't explicitly say anywhere that they ended that exact year. However, Mr. Zahn did state that he asked Lucasfilm about it when he was first outlining the Thrawn books, and was told that the Clone Wars had taken place 35 years before the first movie. Given that the Empire did not form until around the time of Luke's birth (about 15 years after this), the conclusion that the wars did not directly lead into the Emperor's takeover is obvious. He must therefore have used the chaos and destruction they left in their wake to gradually create a politically advantageous situation for himself.

Isn't it possible that the Clone Wars as they were described to Zahn lasted 15 years?