Setting range to last row in a table

Hi everyone,

I'm a complete novice at excel and vba. If you see the attached worksheet, my goal was to have a code that would fill each blank cell in columns A and B with the sum of the cells before it, until it reached another blank cell. I searched online and have found a code that works, see below, however it is a defined range. I will be inputting new data daily and therefore need it to automatically adjust the range to the last row in the table. I've searched the internet for a couple of weeks now trying to find a solution that works to no avail. My current code is:

Sub PickingTotals()
    Dim myCell      As Range
    Dim currentSum  As Double
    For Each myCell In Worksheets("ALL DATA").Range("a2:a287,b2:b287")
        If myCell = vbNullString Then
            myCell = currentSum
            myCell.Interior.Color = 16777215
            currentSum = 0
        Else
            currentSum = currentSum + myCell
        End If
    Next myCell
End Sub

Thank you for your quick reply.

I've copied it over into my spreadsheet, and changed this line

 For thisCol = 1 To 2

to

 For thisCol =25 To 26

as that is where the columns are on my full sheet. When I run the code, it says error "9", Subscript out of range and highlights this column

colSum(thisCol - 1) = colSum(thisCol - 1) + Cells(thisRow, thisCol).Value

.

Is there anything else I should change?

Thank you!

Worked an absolute treat!!! Thank you so much, the amount of time I've spent trying to work it out myself is unbelievable haha.

Thanks again!

Sub PickingTotals1()
    Dim myCell      As Range
    Dim currentSum  As Double
     Dim Rng As Range
     
    With Worksheets("ALL DATA")
        Set Rng = .Range("A2:A" & .Range("A" & .Rows.Count).End(xlUp).Row & ", B2:B" & .Range("A" & .Rows.Count).End(xlUp).Row)
        For Each myCell In Rng
            If myCell = vbNullString Then
                myCell = currentSum
                myCell.Interior.Color = 16777215
                currentSum = 0
            Else
                currentSum = currentSum + myCell
            End If
        Next myCell
    
    End With
End Sub