pre_text: Results of Operations Consolidated Results of Operations The following tables present certain financial data for the periods indicated (dollars in millions):
table: Year ended December 31,
table: 2019 2018 2017
table: Revenues $1,177.2 $1,114.0 $1,051.6
table: Expenses:
table: Operating expenses 646.0 625.4 569.5
table: Depreciation and amortization 236.2 217.0 206.5
table: Transition and integration costs 5.4 6.6 13.1
table: Total expenses 887.6 849.0 789.1
table: Operating income 289.6 265.0 262.5
table: Operating margin 24.6% 23.8% 25.0%
table: Interest expense, net (63.5) (51.7) (57.5)
table: Other expense, net (1.4) (7.1) (12.6)
table: Earnings before income taxes and equity in losses of unconsolidated affiliates 224.7 206.2 192.4
table: Income tax expense (benefit) 41.9 37.7 (61.8)
table: Earnings before equity in losses of unconsolidated affiliates 182.8 168.5 254.2
table: Equity in losses of unconsolidated affiliates, net of tax (74.0) — —
table: Net earnings $108.8 $168.5 $254.2
table: Earnings per share:
table: Net earnings per share attributable to Black Knight common shareholders:
table: Diluted $0.73 $1.14 $1.47
table: Weighted average shares of common stock outstanding:
table: Diluted 148.6 148.2 152.4
question: Analyse this data from a financial earnings document. What was the change in operating income between 2017 and 2018?