The methodology for data mining is based on disaggregation at regional level followed by categorisation using classical clustering approach. Sources for historical and current values are prioritised by experience, state regulator publications, state-of-the-art revision. Trends will be created based on back casting and are subject to stakeholder review. Many regional system operators collect and use energy efficiency and demand response data in system studies. As well consultants, research centers and other entities regularly collect and tabulate energy efficiency and demand response data.