query: #by Jura1, 2015-01-25
  #scales: <1=<1, 1=1-9, 2=10-99, 3=100-999, etc.
  
  SELECT ?scale (COUNT(?quantityvalue) AS ?count)
  {
    ?item wdt:P9180 ?quantityvalue .
      BIND(strlen(STR(ROUND(?quantityvalue))) as ?length)
      BIND(IF(?quantityvalue<1,"<1",?length)   as ?scale)
  }
  GROUP BY ?scale
  ORDER BY ?scale
  LIMIT 100