Average commodity prices and exchange rates for the past three years, which are key drivers of our profit, are  summarized in the following table. Our revenue and gross profit before depreciation and amortization by business unit are summarized in the following table. * Published major supplier selling price in Platts  Metals Week . * Gross profit before depreciation and amortization is a non-GAAP financial measure. See “Use of Non-GAAP Financial Measures” section for further information. US$ Cdn$ 2012 % chg  2011  % chg  2010  2012 % chg  2011  % chg  2010 Copper  (LME cash – $/pound)  3.61 -10% 4.00 +17% 3.42 3.61 -9% 3.96 +13% 3.52 Coal (realized – $/tonne)  193 -25% 257 +42% 181 194 -24% 254 +35% 188 Zinc (LME cash – $/pound)  0.88 -11% 0.99 +1% 0.98 0.88 -10% 0.98 -3% 1.01 Molybdenum (Platts* – $/pound)  13 -13% 15 -6% 16 13 -13% 15 -6% 16 Lead (LME cash – $/pound)  0.94 -14% 1.09 +12% 0.97 0.94 -13% 1.08 +8% 1.00 Exchange rate (Bank of Canada) US$1 = Cdn$  1.00 +1% 0.99 -4% 1.03 Cdn$1 = US$  1.00 -1% 1.01 +4% 0.97 Gross Profit Before  Revenues  Depreciation and Amortization* ($ in millions) 2012 2011 2010 2012 2011 2010 Copper  $ 3,142 $ 3,108 $ 2,509 $ 1,500 $ 1,674 $ 1,462 Coal 4,647 5,641 4,351 2,033 3,306 2,261 Zinc 2,550 2,765 2,363 480 808 715 Energy  4 – – 4 – – Total  $ 10,343 $ 11,514 $ 9,223 $ 4,017 $ 5,788 $ 4,438 Generations 35