Alternatively, you can do it without needing to know all the names of the
formats that might be applied, which is probably more flexible. This picks
up any format ending iwth a percentage.
Function IsPercentFormat(rngCell as range) as boolean
Dim strFormat as String
'note no error traps for multiple cell range
strFormat= rngCell.NumberFormat
If (InStr(1, strFormat, "%", 1)) > 1 Then IsPercentFormat=True
End Function