apache mod_deflate not compressing

Question

Hi, I've done the following to enable and configure mod_deflate in apache running on ubuntu

>sudo a2enmod deflate
>sudo apache2ctl restart
>sudo vi deflate.conf
<IfModule mod_deflate.c>
    AddOutputFilterByType DEFLATE text/html text/plain text/css text/xml application/x-javascript text/javascript application/javascript
    DeflateFilterNote Input input_info
    DeflateFilterNote Output output_info
    DeflateFilterNote Ratio ratio_info
    LogFormat '"%r" %{output_info}n/%{input_info}n (%{ratio_info}n%%)' deflate
    CustomLog /var/log/apache2/deflate_log deflate
</IfModule>
>sudo apache2ctl restart

but it doesn't seem to be compressing any of the served files. Does anyone have any idea what I might be configuring incorrectly?

Cheers.