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Supplemental Information Gas: Btu Factors Navigator Btu Factors: 2008 | 2007 | 2006 Gas Transportation Btu Factors 2006 Illinois - Iowa - Nebraska - South Dakota Effective Month/Year Btu Factor* January 2006 1.016 February 2006 1.021 March 2006 1.014 April 2006 1.014 May 2006 1.012 June 2006 1.007 July 2006 1.012 August 2006 1.007 September 2006 1.009 October 2006 1.007 November 2006 1.008 December 2006 1.011 * 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.