31 primarily due to a stronger Euro relative to the U.S. dollar , and incremental net sales attributable to the results of acquired businesses of $18.1 million partially of fset by lower sales volume of $40.8 million. V olume, as measured by metal pounds sold, decreased by 5.3 million pounds, or 2%, in 201 1 compared to 2010. Economic conditions in Europe remained weak, influencing demand across a broad spectrum of products and regions, particularly in the Iberia region as well as in Algeria partially of fset by the Company's project related activities in Germany and France. Metal-adjusted net sales in the ROW segment increased $279.1 million, or 16%, due to higher sales volume of $1 13.5 million, favorable selling price and product mix of $97.0 million, and favorable foreign currency exchange rate changes of $68.2 million, primarily due to the strengthening of certain currencies in Central and South America relative to the U.S. dollar . V olume, as measured by metal pounds sold, increased by 62.5 million pounds, or 18%, in 201 1 compared to 2010 which is primarily attributable to increase in demand for high-voltage aerial transmission products and low-and medium-voltage distribution cables in Brazil as well as infrastructure investment in Central America. Cost of Sales Cost of sales increased $939.8 million, or 22%, from 2010. The increase in 201 1 as compared to 2010 was principally driven by the increase in volume sold of 8%, the increase in raw material costs, including a 17% increase in the average cost of copper and a 10% increase in the average cost of aluminum as well as an increase in other raw material costs, and an increase due to currency translation of 3%. As noted in Item 1 - Business. the Company's products are raw material intensive with copper and aluminum comprising the major cost components for cable products. At current metal prices, material costs are approximately 85% of total product costs with copper and aluminum metal costs comprising approximately 60% of total product cost for the year ended December 31, 201 1. Gr oss Pr ofit Gross profit increased $62.0 million, or 1 1%, in 201 1 from 2010. The increase in gross profit was primarily due to an increase in volume in North America and ROW and a shift in product mix and pricing in North America. Gross profit as a percentage of sales was 10% and 1 1% in 201 1 and 2010, respectively . Despite volume and related revenue increases for the year gross profit did not increase as a percentage of sales. In the first half of the year gross profit as a percentage of sales increased due to selling prices rising faster than the average cost of metal prices which was of fset in the latter part of the year due to the increased volatility and declines in metal prices. Selling, General and Administrative Expense Selling, general and administrative expense increased $46.0 million, or 14%, in 201 1 from 2010. The increase in SG&A is primarily a result of incremental investment in resources related to the Company's global sales network and product technology as well as increased costs for new market penetration strategies in 201 1 as compared to 2010. The increase in SG&A is also due in part to foreign currency exchange rates in 201 1 as compared to 2010 in the amount of $8.7 million. SG&A as a percentage of metal- adjusted net sales was 6% for 201 1 and 2010, respectively . Operating Income The following table sets forth operating income by segment, in millions of dollars. Operating Income Y ear Ended Dec 31, 2011 Dec 31, 2010 Amount % Amount % North America $ 121.8 53 % $ 96.9 45 % Europe and Mediterranean 30.3 13 % 36.8 17 % ROW 78.0 34 % 80.4 38 % Total operating income $ 230.1 100 % $ 214.1 100 % The increase in operating income for the North America segment of $24.9 million is primarily attributable to benefits from a shift in product mix, as well as a more favorable pricing environment due to an increase in market demand in most product lines, excluding electrical utility distribution products in 201 1, as well as increased sales volume. The increases to operating income were partially of fset by an increase in SG&A expenses of $1 1.8 million in 201 1 as compared to 2010; the SG&A increases were for the reasons noted above. The decrease in operating income for the Europe and Mediterranean segment of $6.5 million was primarily attributable to continued weak demand and pricing due to the economic slowdown in many European end markets, as well as an increase in SG&A expenses of $1 1.0 million in 201 1 as compared to 2010; the SG&A increases were for the reasons noted above. Partially of fsetting these T able of Contents