gPieChart: Who are/have been field operators?

The element which draws the above chart:

<div id="sgvzl_example_query" 
   data-sgvizler-endpoint="http://sws.ifi.uio.no/sparql/npd" 
   data-sgvizler-query="SELECT ?name (count(*) AS ?noOfFields) WHERE{ [] a npdv:Field ; npdv:hasCompany [ npdv:name ?name ] . } GROUP BY ?name ORDER BY ?name" 
   data-sgvizler-chart="gPieChart" 
   data-sgvizler-loglevel="2" 
   style="width:800px; height:400px;"/>

The results of the query in gTable

Same query, different charts

Not all charts may be well-suited for displaying this dataset.

gBarChart

gColumnChart