how to answer why you are leaving current job?

Tell them that you are seeking a position with better benefits or more room for advancement.

I am satisfied and perfect in doing the current job. For my better future i am joining as an superior in another company.

Most of intelligence poeple not working in one organisation more than five years.
If you work like that your knowledge skills level will be depend on your colleagues knowledge and all your working atmosphere.

To get different company, poeple and country knowledge, to improve future life style and ofcourse for superior position and super earnings.

Everybody has to change their job after surtain period because when you change a job you get new knowledge of the various organisations. Every management has their own policies and terms and conditions and if you work with various management you can take best possible decision on top level which is not possible in the one organisation.

As a Business Objects Developer throughout my Career I worked with a Small and Big Companies as Contractor and my Past project was also as a contract base. My Project was over (put your last project date) and I am looking for a New opportunity where I can explore my expertise.