Get ChEMBL protein classification level breakdown

Statement: 
Get ChEMBL according the protein classification level breakdown $level$ (e.g. L1).
A limit of results per page $number$ (e.g.10)
Query: 
PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#> PREFIX owl: <http://www.w3.org/2002/07/owl#> PREFIX xsd: <http://www.w3.org/2001/XMLSchema#> PREFIX dc: <http://purl.org/dc/elements/1.1/> PREFIX dcterms: <http://purl.org/dc/terms/> PREFIX dbpedia2: <http://dbpedia.org/property/> PREFIX dbpedia: <http://dbpedia.org/> PREFIX foaf: <http://xmlns.com/foaf/0.1/> PREFIX skos: <http://www.w3.org/2004/02/skos/core#> PREFIX cco: <http://rdf.ebi.ac.uk/terms/chembl#> SELECT ?parent ?parent_name (COUNT(DISTINCT ?parent_tc) AS ?parent_desc_count) WHERE { ?parent cco:classLevel '??level' ; skos:prefLabel ?parent_name ; cco:hasTargetDescendant ?parent_tc . } GROUP BY ?parent ?parent_name limit ??number