query: embed.html##defaultView:LineChart
  SELECT (str(?year) as ?yr) (COUNT(DISTINCT ?item) as ?ct) 
  {
      ?item wdt:P27 wd:Q142 .
      ?item wdt:P569 ?b . 
      FILTER(YEAR(?b) > 1900 ) 
      BIND( YEAR(?b) as ?year) 
  }  
  GROUP BY ?year 