query: SELECT DISTINCT ?item ?country ?age ?retirement ?old (ROUND((NOW() - ?st)/365.2425) AS ?years_in_office)
  WHERE
  { 
    ?country wdt:P31 wd:Q3624078 ; p:P6 ?statement .    
    ?statement ps:P6 ?item .
    ?country wdt:P6 ?item .
    FILTER NOT EXISTS { ?statement pq:P582 ?x } 
    ?item wdt:P569 ?dob . BIND(ROUND((NOW() - ?dob)/365.2425) AS ?age)
    FILTER (!isBLANK(?item))
    OPTIONAL { ?country wdt:P3001 ?retirement }
    OPTIONAL { ?statement pq:P580 ?st }
    BIND(COALESCE( ?retirement, 65 ) as ?old)
    FILTER (?age >= ?old)
  }
  ORDER BY ?dob ?country