Mistake on job application

[Wineloffa]

I have a job interview next Thursday for an internal position which I really want. It's a sales job and on my application form, I put down my total sales achieved for the past year to demonstrate how capable I am. However, I was going through my figures today and realise that I've accidentally put the wrong figure in the form! My final 2 campaigns for last year were handled by a new member of staff to alleviate my workload however their figures were included in the year end total - so I've £350k on the form when it should read £320k!

The question is what do I do now? Do I contact HR and explain beforehand what's happened? Do I mention it in the interview or say nothing at all?? I don't want them to think I've lied, it's a genuine mistake!!
But
Any HR people about who can advise?

Just mention it when you get there, I think.

Just say exactly what you just said. When I was rereading my CV prior ro this interview I realised that two projects I handed over have been included in my figures the £350k should be £320.

Thank you. Honesty is the best policy and the people on the panel are aware of these projects so will hopefully understand what an easy mistake it is to make.