What was the percentage change in Operating income between Quarter Ended  June and September?
{"Sales, net": {"December 31, 2019": 338268.0, "September 30, 2019": 175127.0, "June 30, 2019": 134810.0, "March 31, 2019": 140743.0}, "Gross Profit": {"December 31, 2019": 112295.0, "September 30, 2019": 73491.0, "June 30, 2019": 64126.0, "March 31, 2019": 65740.0}, "Restructuring Expense": {"December 31, 2019": 1418.0, "September 30, 2019": 152.0, "June 30, 2019": 1795.0, "March 31, 2019": 1673.0}, "Operating income": {"December 31, 2019": 22202.0, "September 30, 2019": 9390.0, "June 30, 2019": 11005.0, "March 31, 2019": 11791.0}, "Income from continuing operations, net of income taxes": {"December 31, 2019": 10479.0, "September 30, 2019": 7256.0, "June 30, 2019": 23373.0, "March 31, 2019": 15387.0}, "Loss (income) from discontinued operations, net of income taxes": {"December 31, 2019": -210.0, "September 30, 2019": 375.0, "June 30, 2019": 8324.0, "March 31, 2019": -9.0}, "Net Income": {"December 31, 2019": 10269.0, "September 30, 2019": 7631.0, "June 30, 2019": 31697.0, "March 31, 2019": 15378.0}, "Income from continuing operations attributable to noncontrolling interest": {"December 31, 2019": 5.0, "September 30, 2019": 10.0, "June 30, 2019": 11.0, "March 31, 2019": 8.0}, "Net income attributable to Advanced Energy Industries, Inc.": {"December 31, 2019": 10264.0, "September 30, 2019": 7621.0, "June 30, 2019": 31686.0, "March 31, 2019": 15370.0}, "Continuing Operations: -- Basic earnings per share": {"December 31, 2019": 0.27, "September 30, 2019": 0.19, "June 30, 2019": 0.61, "March 31, 2019": 0.4}, "Continuing Operations: -- Diluted earnings per share": {"December 31, 2019": 0.27, "September 30, 2019": 0.19, "June 30, 2019": 0.61, "March 31, 2019": 0.4}, "Discontinued Operations: -- Basic loss per share": {"December 31, 2019": -0.01, "September 30, 2019": 0.01, "June 30, 2019": 0.22, "March 31, 2019": "$ \u2014"}, "Discontinued Operations: -- Diluted loss per share": {"December 31, 2019": -0.01, "September 30, 2019": 0.01, "June 30, 2019": 0.22, "March 31, 2019": "$ \u2014"}, "Net Income: -- Basic earnings per share": {"December 31, 2019": 0.27, "September 30, 2019": 0.2, "June 30, 2019": 0.83, "March 31, 2019": 0.4}, "Net Income: -- Diluted earnings per share": {"December 31, 2019": 0.27, "September 30, 2019": 0.2, "June 30, 2019": 0.82, "March 31, 2019": 0.4}}
operating_income_september = df["Operating income"]["September 30, 2019"]
operating_income_june = df["Operating income"]["June 30, 2019"]
answer = (operating_income_september - operating_income_june) / operating_income_june * 100.0