pre_text: Cubic Global Defense Sales: CGD sales decreased 2% to $317.9 million in 2019 compared to $325.2 million in 2018. The timing of sales recognition was impacted by the adoption of ASC 606. Under ASC 606, a number of our CGD contracts, most significantly in air combat training and ground live training, for which revenue was historically recorded upon delivery of products to the customer, are now accounted for on the percentage-of-completion cost-to-cost method of revenue recognition. For fiscal 2019, sales were lower from air combat training systems, simulation product development contracts, and international services contracts, partially offset by higher sales from ground combat training systems. The average exchange rates between the prevailing currencies in our foreign operations and the U.S. dollar resulted in a decrease in CGD sales of $3.2 million for 2019 compared to 2018. Amortization of Purchased Intangibles: Amortization of purchased intangibles included in the CGD results amounted to $0.6 million in 2019 and $1.1 million in 2018. Operating Income: CGD operating income increased by 39% to $23.0 million in 2019 compared to $16.6 million in 2018. For fiscal 2019, operating profits improved primarily due to the results of cost reduction efforts, including headcount reductions designed to optimize our cost position, and reduced R&D expenditures. Operating profits were higher from increased sales of ground combat training system sales but were lower on decreased sales from air combat training systems, simulation product development contracts, and international services contracts. The average exchange rates between the prevailing currency in our foreign operations and the U.S. dollar had no significant impact on CGD operating income between 2018 and 2019. Adjusted EBITDA: CGD Adjusted EBITDA was $32.8 million in 2019 compared to $26.3 million in 2018. The increase in Adjusted EBITDA was primarily driven by the same factors that drove the increase in operating income described above. Adjusted EBITDA for CGD increased by $3.1 million in 2019 as a result of the adoption of the new revenue recognition standard.
table: Fiscal 2019 Fiscal 2018 % Change
table: (in millions)
table: Sales $  317.9 $  325.2 (2)%
table: Operating income 23.0 16.6 39
table: Adjusted EBITDA 32.8 26.3 25
question: Analyse this data from a financial earnings document. What is the change in the amount of sales from 2018 to 2019?