SPARQL query to get the total utility consumption per month for a building

utilityValueByMonth

prefix xsd: <http://www.w3.org/2001/XMLSchema#> 
prefix gol: <http://cofog01.data.scotland.gov.uk/def/golspie/> 
prefix qb:  <http://purl.org/linked-data/cube#> 
prefix buildingCode:  <http://cofog01.data.scotland.gov.uk/id/facility/> 
prefix fn: <http://www.w3.org/2005/xpath-functions#> 
prefix util: <http://cofog01.data.scotland.gov.uk/def/golspie/> 
prefix skos: <http://www.w3.org/2004/02/skos/core#>

select ?month (sum(?o) as ?val )

where {  

?slice gol:refBuilding buildingCode:AB0001 ; 
       gol:reportDateTime ?dt ; 
       qb:sliceStructure gol:sliceByDay; 
       qb:observation ?obs .

?obs  gol:utilityConsumption ?o ; 
      gol:refUtility util:electricity . 

filter (xsd:dateTime(?dt) >= '2013-06-11T00:00:00Z'^^xsd:dateTime && 
        xsd:dateTime(?dt) < '2013-12-11T00:00:00Z'^^xsd:dateTime)
}
group by (month(?dt) as ?month)
order by ?month

limit 2000