Query is not valid when filtering datetime in REST OData

I'm trying to get the items from a list "MyList". I'm using the following Url:

/_api/web/lists/getbytitle('MyList')/items?$filter=year(Created) eq 2014

But I got the exception :

{"odata.error": {"code": "-1, Microsoft.SharePoint.SPException","message": {"lang": "en-US","value": "The query is not valid."
        }
    }
}

What's the problem?

Thanks a lot.