Using LIKE expression problem..

Hi everybody..

    

     Before anything else I would like to thank all those person who answers
my previous question. again thank you very much

 

This is my question .

    

     In my query .. Select * from table1 where lastname LIKE  'PUNCIA%'..

 

In the query plan ..it uses seq scan rather than index scan .. why ? I have
index on lastname, firtname. 

 

 

Thanks