– where invoiced data existed for an office for part of the  reporting period, determining daily electricity consumed  for that part of the reporting period and extrapolating  this out to the remainder of the reporting period for that  office  – where historical data exists for the office this is used to  estimate the electricity consumed for the reporting  period  – where no invoice data was available for a particular  office, estimating electricity consumed for that office  based on the Net Lettable Area of the office and the  average electricity consumption per square metre of  other offices in the same region. 3.2.1.2 Total electricity consumed  Approximately 85 per cent of the electricity data for the  reporting period was obtained directly from actual tenancy or  building data. The remaining 15 per cent of energy  consumption was estimated by either:  Emission factors outlined in section 3.2.2 have then been  applied to determine the equivalent indirect emissions  associated with electricity consumed (Scope 2 emissions).  Air travel data was based off reports provided by  International SOS, the organisation contracted to monitor  MGL staff travel and provide emergency assistance where  required. Emission factors outlined in section 3.2.2 have then been  applied to mileage to determine the equivalent indirect  emissions associated with business air travel (Scope 3  emissions).  3.2.1.3 Other indirect emissions associated with business  air travel (Scope 3 emissions) 3.2.2 Measurement of GHG emissions  The following emissions factors have applied in calculating  GHG emissions (tonnes CO$_{2}$-e):  Scope 2 emissions factors used for Australian and United  States offices, and Scope 3 emissions factors for all air travel  include greenhouse gases in addition to carbon dioxide and  are expressed in carbon dioxide equivalents (CO$_{2}$-e) as  stipulated within the associated reference documents.  Scope 2 emission factors used for the United Kingdom and  remaining office locations only comprise carbon dioxide  emissions (CO$_{2}$) as stipulated within the reference  documents. The jurisdictional variance in approaches to  Scope 2 methodology had no material effect on outcome.  All carbon offsets purchased were registered under the  international Gold Standard issued by the Gold Standard  Foundation, Voluntary Carbon Standard issued by the VCS  Association or US Climate Action Reserve protocol. 3.3 Carbon offsets purchased and retired  Component  Reference documents Australian offices  National Greenhouse and Energy  Reporting (Measurement) Determination  2013  for the calculation of greenhouse  gas (GHG) emissions. EMEA offices  The electricity emission factors as  published in Department for  Environment Food and Rural Affairs  (DEFRA) 2013 Government GHG  Conversion Factors for Company  Reporting: Methodology Paper for  Emission Factors  Americas offices  The Climate Registry Information  System (CRIS) (2014)  Asia offices  The electricity emission factors as  published in Department for  Environment Food and Rural Affairs  (DEFRA) 2013 Government GHG  Conversion Factors for Company  Reporting: Methodology Paper for  Emission Factors  Air travel  The emission factors as published in  Department for Environment Food and  Rural Affairs (DEFRA) 2013 Government  GHG Conversion Factors for Company  Reporting: Methodology Paper for  Emission Factors  Macquarie Group Limited and its subsidiaries  macquarie.com.au  2014 Annual Financial Report  Environmental, Social and Governance Appendix  Independent review  continued  222 