Morerecently, a numberof resource-dependent countrieshave become interested in measuringdepreciationof their naturalassetsandadjustingtheir GDPs environmentally.
Three-quarters of the Birmingham, Ala. energy and utility company's operating income (earnings before interest, taxes and depreciation) comes from pulling natural gas out of the ground, specifically the 1.7 trillion cubic feet worth of proved deposits it has acquired in the last 11 years.