pre_text: Operating Income Our operating income in fiscal year 2018 increased to $189.3 million, or 8.8 percent of net sales as compared with $121.5 million, or 6.8 percent in net sales in fiscal year 2017. Excluding surcharge revenue and special items, adjusted operating margin was 10.6 percent for the fiscal year 2018 and 8.0 percent for fiscal year 2017. The increase in the operating margin reflects the stronger demand and improved product mix coupled with operating cost improvements partially offset by higher variable compensation expense compared to fiscal year 2017. Operating income has been impacted by special items. The following presents our operating income and operating margin, in each case excluding the impact of surcharge on net sales and the loss on divestiture of business. We present and discuss these financial measures because management believes removing the impact of these items provides a more consistent and meaningful basis for comparing results of operations from period to period. See the section “Non-GAAP Financial Measures” below for further discussion of these financial measures.
table: Fiscal Year
table: ($ in millions) 2018 2017
table: Net sales $2,157.7 $1,797.6
table: Less: surcharge revenue 365.4 239.2
table: Net sales excluding surcharge revenue $1,792.3 $1,558.4
table: Operating income $189.3 $121.5
table: Special items:
table: Loss on divestiture of business — 3.2
table: Adjusted operating income excluding special items $189.3 $124.7
table: Operating margin 8.8% 6.8%
table: Adjusted operating margin excluding surcharge revenue and special items 10.6% 8.0%
question: Analyse this data from a financial earnings document. What was the change in operating income in 2018 from 2017?