Using Crystal Reports 10 -

I need to use a “formula” to calculate "Average Monthly Usage" for the past 12 months.

My ODBC table.fields are:

{FootageSummarySerial.FiscalYear}

{FootageSummarySerial.FiscalMonth}

{FootageSummarySerial.ActualUsage}

My code so far is:

IF {FootageSummarySerial.FiscalYear} = 2008

AND {FootageSummarySerial.FiscalMonth} = 1

THEN

AVERAGE ({FootageSummarySerial.ActualUsage})

ELSE 0

I need to include Fiscal Years 2007, 2006, and 2005, and all 12 Fiscal Months into the calculation.

I apppreciate any help in completing this formula.