Specifies the number of categories (or units on a scatter chart) that the trend line extends before the data for the series that is being trended. On no-scatter charts, the value shall be 0 or 0.5.

'Declaration
 
Property Backward As Double

'Usage
 
Dim instance As IExcelTrendLine
Dim value As Double
 
instance.Backward = value
 
value = instance.Backward

double Backward {get; set;}