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Supplemental Information Gas: Btu Factors Navigator Btu Factors: 2008 | 2007 | 2006 Gas Transportation Btu Factors 2008 Illinois - Iowa - Nebraska - South Dakota Effective Month/Year Btu Factor* January 2008 1.016 February 2008 1.017 March 2008 1.018 April 2008 1.017 May 2008 1.016 June 2008 1.016 July 2008 1.018 August 2008 1.017 September 2008 1.016 October 2008 1.023 November 2008 1.020 December 2008 1.019 * This figure is a true weighted Btu calculation based on the weighted average of all gas flowing to    the system on NNG, NGPL, ANR and NBPL pipelines. Navigator Btu Factors: 2008 | 2007 | 2006 For Your Home | For Your Business | Safety | Rates | Energy Efficiency | Economic Development | Environmental Efforts About Us | Careers | News Room | Storm Center | Wind Energy | Contact | Streetlight Repair Request | System Outage Watch | Energy Choice | For Contractors | For Landlords | ©2008 MidAmerican Energy Holdings Company. All rights reserved.