See if this helps...

Declare @curYearStart datetime

,@prevYearStart datetime;

Set @curYearStart = dateadd(year, datediff(year, 0, getdate()), 0);

Set @prevYearStart = dateadd(year, -1, @curYearStart);

;With currentYTD (Area, Source, Total)

As (Select Area

,Src

,count(Distinct Account_No)

From #dim1

Where Filter_Code Not In ('4', '9', 'Unknown')

And [Date] >= @curYearStart

And [Date] < dateadd(day, datediff(day, 0, getdate()), 0)

Group By Area

,Src

), previousYTD (Area, Source, Total)

As (Select Area

,Src

,count(Distinct Account_No)

From #dim1

Where Filter_Code Not In ('4', '9', 'Unknown')

And [Date] >= @prevYearStart

And [Date] < @curYearStart

Group By Area

,Src

)

Select curYTD.Area

,curYTD.Source

,curYTD.Total As 'YTD 2010'

,prevYTD.Total As 'YTD 2009'

,(curYTD.Total - prevYTD.Total) As Variance

From currentYTD curYTD

Join previousYTD prevYTD On prevYTD.Area = curYTD.Area

And prevYTD.Source = curYTD.Source;