Fill/Copy Down Blank Cells Issue

I'm trying to copy down blank cells based on the value above it. But I'm not certain how to handle the last item to fill down the blanks for the range selected.

This is the basic code which works except for copying the last item. I think I need to somehow include an 'end' of the range?

Sub FillBlanks()
    
    With Intersect(Selection, ActiveSheet.UsedRange)
        On Error Resume Next
        Selection.SpecialCells(xlCellTypeBlanks).Select
        Selection.FormulaR1C1 = "=R[-1]C"
        .Value = .Value
    End With

End Sub