PREFIX nmo: <http://nomisma.org/ontology#>
PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#>
SELECT ?authName (COUNT(?type) AS ?types) WHERE {
?type a nmo:TypeSeriesItem ; nmo:hasAuthority ?auth .
?auth rdfs:label ?authName .
} GROUP BY ?authName ORDER BY DESC(?types)