Crystal Reports XI - Paramater Field Limit?

Is there a limit of database fields that can be displayed when using a parameter field prompt?

I'm designing a report with customers and sales figures with a database of about 2,000 customers. When I create a parameter field to be able to select which customer I'd like to see, only about 790 database results are returned, instead of the full 2,000.

Any ideas of what could be going on here?