Turning off automatic ranking on words

Hi,

How can I turn off the positioning since I won't be needing it.

SELECT to_tsvector('english','in the list of stop words');
        to_tsvector
----------------------------
 'list':3 'stop':5 'word':6

I don't need to store the positions as shown in the example because I rank according to date/price etc..

Thank you, James