UBB.threads PHP Forum Software Community Forums Resources and Customizing How Do I? Number of members/ forum stats

My 'Forum Stats' island shows a certain number of 'members'.

However the number of 'users' in ubbt_USERS has a figure that is different by a count of 11.

I need the correct count for a script I'm writing.

Can someone please advise the correct table to use? And perhaps why there is a difference of 11?

Thanks