Across all product areas International product sales increased $0.3 million, or 1.3 percent in the third quarter of 2012 as compared to the same quarter of 2011. Had the same foreign currency rates been in effect in the quarter ended September 30, 2012 as were in effect in the third quarter in 2011, the U.S. dollar reported value of product sales would have been higher by $1.4 million for this quarter.
Management believes percentage sales growth in constant currency is an important metric for evaluating our operations because the impact of changing foreign currency exchange rates may not provide an accurate baseline for analyzing trends in our business. Percentage sales growth in constant currency is calculated by translating current year sales at prior year average foreign currency exchange rates. Constant currency is a non-GAAP measure and it should not be considered as a substitute for measures prepared in accordance with GAAP.
GROSS PRODUCT MARGIN
Gross product margin as a percentage of product sales was 68.3 percent for the third quarter of 2012 compared to 67.9 percent for the third quarter of 2011.INCOME FROM OPERATIONS Income from operations for the third quarter of 2012 was $13.7 million compared to $4.4 million for the same period in 2011. Operating margin for the third quarter of 2012 was 15.7 percent compared to 5.2 percent for the same period in 2011. Under the short-term incentive plan for 2012 approved by the Board of Directors, Adjusted Operating Margin is a key metric for purposes of evaluating business performance. Adjusted Operating Margin is Operating Margin adjusted for investigation and restatement related costs. Investigation and restatement related costs were 2.5 percent and 7.2 percent of total revenue for the third quarters of 2012 and 2011, respectively, and Adjusted Operating Margin was 18.2 percent and 12.4 percent for these same periods. Adjusted Operating Margin is a non-GAAP measure of profitability and it should not be considered as a substitute for measures prepared in accordance with GAAP.