query: #Cats
  SELECT ?item ?itemLabel ?GDP WHERE {
    ?item wdt:P30 wd:Q15.#continent is Africa
    SERVICE wikibase:label { bd:serviceParam wikibase:language "[AUTO_LANGUAGE],en". }#labels are in English
    ?item wdt:P31 wd:Q6256.#instanc of country
    ?item wdt:P2131 ?GDP#nominal GDP
    FILTER (?GDP > 38616536131)
  }
    ORDER BY DESC (?GDP)