sgvizler: Europeana Spanish articles by year

HTML

<script src="//cdnjs.cloudflare.com/ajax/libs/jquery/1.9.0/jquery.js"></script>
<script src="https://www.google.com/jsapi"></script>
<script src="http://beta.data2000.no/sgvizler/release/0.6/sgvizler.js"></script>
<div id="ex"
   data-sgvizler-endpoint="http://europeana-test.ontotext.com/sparql.srj"
   data-sgvizler-query="
PREFIX dc: <http://purl.org/dc/elements/1.1/>
PREFIX ore: <http://www.openarchives.org/ore/terms/>
PREFIX edm: <http://www.europeana.eu/schemas/edm/>
PREFIX dct: <http://purl.org/dc/terms/>

select ?date (count(*) as ?c)  {
  ?proxy dc:type 'info:eu-repo/semantics/article'.
  optional {?proxy dct:issued ?date1}
  optional {?proxy dc:date ?date2}
  bind (xsd:integer(substr(coalesce(?date1,?date2),1,4)) as ?date)
}
group by ?date 
having (?c>1)
order by ?date"
   data-sgvizler-chart="google.visualization.ColumnChart"
   data-sgvizler-chart-options="vAxis.logScale=true|vAxis.textPosition=in|legend.position=none|bar.groupWidth=80%"
   style="width:700px; height:500px; border:1 solid black; display: nline-block;"></div>

JavaScript

$(document).ready(function () {
    sgvizler.defaultEndpointOutputFormat('json').containerDrawAll();
});