Get "trimmed minimum", similiar to Excel TRIMMEAN Function - excel

Question

I would like to implement a custom function into Excel which returns the minimum of a trimmed data sample.
Two inputs:
Data
Percentage, which states how many data points from the original data sample should be excluded
My first draft (seen below) misses two features right now:
When I use the function and select a whole column (e. g. =TrimMIN(A:A)) it takes takes a long time
I need to sort the input Range 'data' before trimming it but the line 'data.Cells.Sort' is not working
Looking forward to get get some ideas on those two issues.
My code:
Function TrimMIN(data As Range, percentage As Double) As Double
Dim dataNew As Range
Dim dataNewS As Variant
Dim diff, counter, upper, lower, countDataNew As Double
counter = 0
'data.Cells.Sort
diff = Round(data.Count * percentage / 2, [0])
Debug.Print "diff= " & diff
upper = data.Count - diff
lower = diff
countDataNew = data.Count - diff - diff
'Application.Min(data)
'Debug.Print "upper= " & upper
'Debug.Print "lower= " & lower
'Debug.Print "data.count= " & data.count
'Debug.Print "countDataNew= " & countDataNew
Dim cel As Range
For Each cel In data.Cells
counter = counter + 1
'Debug.Print "counter= " & counter
Debug.Print "celValue= " & cel.Value
If counter > lower And counter <= upper Then
'Debug.Print "counter in range, counter is " & counter
If Not dataNew Is Nothing Then
' Add the 2nd, 3rd, 4th etc cell to our new range, rng2
' this is the most common outcome so place it first in the IF test (faster coding)
Set dataNew = Union(dataNew, cel)
Else
' the first valid cell becomes rng2
Set dataNew = cel
End If
End If
Next cel
'Debug.Print "dataNew.count " & dataNew.count
TrimMIN = Application.Min(dataNew)
End Function

Answer 1

This is a working function.
Ideally it is up to you to place an appropriate range as argument to the funtion...
Public Function TrimMin(data As Range, percentage As Double) As Double
Dim usedData As Variant
'avoid calculating entire columns or rows
usedData = Intersect(data, data.Parent.UsedRange).Value
Dim x As Long, y As Long
x = UBound(usedData) - LBound(usedData) + 1
y = UBound(usedData, 2) - LBound(usedData, 2) + 1
Dim arr() As Variant
ReDim arr(1 To x * y)
Dim i As Long, j As Long, counter As Long
counter = 1
For i = 1 To x
For j = 1 To y
If Application.WorksheetFunction.IsNumber(usedData(i, j)) Then
arr(counter) = usedData(i, j)
counter = counter + 1
End If
Next j
Next i
ReDim Preserve arr(1 To counter - 1)
Dim diff As Long
diff = Round((counter - 1) * percentage / 2, 0) + 1
'use the worksheet function to obtain the appropriate small value
TrimMin = Application.WorksheetFunction.Small(usedData, diff)
End Function