Comparison of adjacent cells in one column based on key value present in some other column

Hi,

Please check the attached spread sheet.

For the Key value1 in Column A, the years are same in column D, So, I do not need any data for this.

But for Key value2 in Column A, the years has to be compared with adjacent cells with same key value.
The missing years has to be captured in a sheet and it is attached.

For e.g. Key value2 in A4 in is having years 2000,2004,2005,2006.
This key value2 is having some more years in column D.
The missing years for this key value2 (A4) are 2001,2002,2003,2007,2008 when compared to other cells (years) in Column D for the same key value2.
This missing data has to be presented as given in the format shown in Expected output section of the attached spreadsheet.
This has to be repeated for all the key values present in column A.

I've around 3000 rows like this, to do this exercise.
Can you please help?