Question: How many suppliers did the Newcastle city council use for education?
SPARQL:
 select count(distinct(?supplier)) as ?result from <http://linkedspending.aksw.org/newcastle-city-council-payments-over-500> { ?obs qb:dataSet ls:newcastle-city-council-payments-over-500. ?obs lso:newcastle-city-council-payments-over-500-service-area "EDUCATION". ?obs lso:newcastle-city-council-payments-over-500-to ?supplier. }