What is the percentage change in gains (losses) on equity investments, net from 2017 to 2019?
{"(In Millions)": {"Dec 28,": 2019, "Dec 29,": 2018, "Dec 30,": 2017}, "Ongoing mark-to market adjustments on marketable equity securities": {"Dec 28,": 277, "Dec 29,": -129, "Dec 30,": "$ \u2014"}, "Observable price adjustments on non-marketable equity securities": {"Dec 28,": 293, "Dec 29,": 202, "Dec 30,": "\u2014"}, "Impairment charges": {"Dec 28,": -122, "Dec 29,": -424, "Dec 30,": -833}, "Sale of equity investments and other": {"Dec 28,": 1091, "Dec 29,": 226, "Dec 30,": 3484}, "Gains (losses) one equity investments, net": {"Dec 28,": 1539, "Dec 29,": -125, "Dec 30,": 2651}, "Interest and other, net": {"Dec 28,": 484, "Dec 29,": 126, "Dec 30,": -349}}
gains_2019 = df["Gains (losses) one equity investments, net"]["Dec 28,"]
gains_2018 = df["Gains (losses) one equity investments, net"]["Dec 30,"]
answer = (gains_2019 - gains_2018) / gains_2018 * 100.0