Well... I'd suggest to work on data instead of datagridview cells.
Here is an idea:
Sub Main()
Dim numbers AS Integer() = New Integer(){8, 9, 1, 10, 11, 2, 12, 13, 3, 3, 5, 14, 15, 16, 17, 18, 8, 8, 8, 8, 19, 19}
Dim result As List(Of Tuple(Of Integer, Integer)) = numbers. _
OrderByDescending(Function(x) x). _
GroupBy(Function(x) x). _
SelectMany(Function(grp, i) grp. _
Select(Function(g) New Tuple(Of Integer, Integer)(i+1 , g))). _
ToList()
'you can use result to display value + rank
End Sub
Result:
Rank Value
1 19
1 19
2 18
3 17
4 16
5 15
6 14
7 13
8 12
9 11
10 10
11 9
12 8
12 8
12 8
12 8
12 8
13 5
14 3
14 3
15 2
16 1