MySQL Date field

I have a mySQL database with a date field. I essentially use the code
that is built by the scaffolding script to create new records in the
database.

On the create record page (http://hostname/classname/new) the date
fields (for date of birth for example) have dropdown menus to enforce
data validity. The problem is that the years only extend from 2001 to
2011. How do I go about fixing this?

Thanks,
Ben