query: embed.html##Battles per year per continent and country last 80 years (animated)
  
  #defaultView:BarChart
  SELECT (SAMPLE(?_continentLabel) AS ?contient) (COUNT(?_country) AS ?battles) (SAMPLE(?_countryLabel) AS ?_countryLabel) (SAMPLE(?year) AS ?year)  WHERE {
    ?subj wdt:P31 wd:Q178561.
    OPTIONAL { ?subj wdt:P580 ?d1. }
    OPTIONAL { ?subj wdt:P585 ?d2. }
    OPTIONAL { ?subj wdt:P582 ?d3. }
    BIND(IF(!BOUND(?d1), IF(!BOUND(?d2), ?d3, ?d2), ?d1) AS ?date)
    BIND(str(YEAR(?date)) AS ?year)
    ?subj wdt:P276 ?_loc.
    ?_loc wdt:P17 ?_country.
    ?_country wdt:P30 ?_continent.
    ?_country rdfs:label ?_countryLabel.
    ?_continent rdfs:label ?_continentLabel.
    
    BIND((NOW()) - ?date AS ?distance)
    FILTER(BOUND(?year))
    FILTER((LANG(?_countryLabel)) = "en")
    FILTER((LANG(?_continentLabel)) = "en")
    FILTER((0 <= ?distance) && (?distance < 31 * 12 * 80))
  }
  GROUP BY ?year ?_country
  ORDER BY ?_countryLabel