Try this
$("#datepicker").datepicker({
format: "yyyy",
viewMode: "years",
minViewMode: "years"
});
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/bootstrap-datepicker/1.6.4/js/bootstrap-datepicker.js"></script>
<link href="https://cdnjs.cloudflare.com/ajax/libs/bootstrap-datepicker/1.6.4/css/bootstrap-datepicker.css" rel="stylesheet"/>
<script src="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/js/bootstrap.min.js"></script>
<link href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap.min.css" rel="stylesheet"/>
<input type="text" id="datepicker" />
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