If you have Excel 2016, you can use this or UDF is the way to go for you as given by
Rick Rothstein :
Unknown
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[TD="align: right"]03/17/2018[/TD]
[TD="align: right"]1[/TD]
[TD="align: right"]2018[/TD]
[TD="align: center"]3[/TD]
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[TD="align: right"]1[/TD]
[TD="align: right"]2018[/TD]
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[TD="align: right"]1[/TD]
[TD="align: right"]2018[/TD]
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[TD="align: right"]03/06/2017[/TD]
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[TD="align: right"]2017,2016[/TD]
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[TD="align: right"]01/01/2016[/TD]
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[TD="align: right"]2017,2016[/TD]
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[TD="align: right"]2[/TD]
[TD="align: right"]2017,2016[/TD]
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[TD="align: right"]12/01/2017[/TD]
[TD="align: right"]3[/TD]
[TD="align: right"]2017[/TD]
[TD="align: center"]9[/TD]
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[TD="align: right"]3[/TD]
[TD="align: right"]2017[/TD]
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Sheet13
[TABLE="width: 85%"]
<tbody>[TR]
[TD]
Array Formulas[TABLE="width: 100%"]
<tbody>[TR]
[TH]Cell[/TH]
[TH="align: left"]Formula[/TH]
[/TR]
[TR]
[TH]C2[/TH]
[TD="align: left"]{=TEXTJOIN(
",",,IF(($B$2:$B$9=B2)*($A$2:$A$9<>""),YEAR($A$2:$A$9),""))}[/TD]
[/TR]
</tbody>[/TABLE]
Enter the formula with "Ctrl+Shift+Enter". Only Pressing "Enter" will result in formula giving error or incorrect result. If entered correctly, Excel will surround with curly braces {}.
Note: Do not try and enter the {} manually yourself[/TD]
[/TR]
</tbody>[/TABLE]