Whats meaning of web analytics report data details ?

Hello,

I have doubts on below details about web analytic report found on following URL :

_layouts/WebAnalytics/Report.aspx?t=SummaryReport&l=sc

If Total Number of Daily Unique Visitors current value == 8,729 and Total Number of Daily Unique Visitors previous value == 10,515

Then , latest day Total Number of Daily Unique Visitors , difference would be 10515-8729 == 1786 ?????

But latest day Number of Daily Unique Visitors report shows461

I am not sure how its being calculated , would you please clarify ??? Also would you please explain whatTrend Percentage meant for ?

Thanks and Regards,

Dipti Chhatrapati