pre_text: Note 16. Share-Based Compensation Share-Based Compensation Expense The following table presents the details of the Company's share-based compensation expense (in millions): (1) During the year ended March 31, 2019, $17.2 million of share-based compensation expense was capitalized to inventory, and $14.9 million of previously capitalized share-based compensation expense in inventory was sold. During the year ended March 31, 2018, $11.9 million of share-based compensation expense was capitalized to inventory and $13.8 million of previously capitalized share-based compensation expense in inventory that was sold. During the year ended March 31, 2017, $11.3 million of share-based compensation expense was capitalized to inventory. The amount of sharebased compensation included in cost of sales during fiscal 2017 included $14.5 million of previously capitalized sharebased compensation expense in inventory was sold and $4.2 million of share-based compensation expense related to the Company's acquisition of Atmel that was not previously capitalized into inventory. The amount of unearned share-based compensation currently estimated to be expensed in the remainder of fiscal 2020 through fiscal 2024 related to unvested share-based payment awards at March 31, 2019 is $253.4 million. The weighted average period over which the unearned share-based compensation is expected to be recognized is approximately 1.88 years.
table: Year Ended March 31,
table: 2019 2018 2017
table: Cost of sales (1) $14.9 $13.8 $18.7
table: Research and development 72.0 42.5 46.8
table: Selling, general and administrative 62.3 36.9 62.6
table: Special (income) charges and other, net 17.2 — —
table: Pre-tax effect of share-based compensation 166.4 93.2 128.1
table: Income tax benefit 35.5 28.3 44.2
table: Net income effect of share-based compensation $130.9 $64.9 $83.9
question: Analyse this data from a financial earnings document. What was the change in the cost of sales between 2017 and 2018?