What was the change in Net operating loss carryforward between 2018 and 2019?
{"Deferred tax assets: -- Deferred income on shipments to distributors": {"2019": "$\u2014", "2018": 39.1}, "Deferred tax assets: -- Inventory valuation": {"2019": 45.0, "2018": 10.7}, "Deferred tax assets: -- Net operating loss carryforward": {"2019": 94.3, "2018": 101.1}, "Deferred tax assets: -- Capital loss carryforward": {"2019": 9.6, "2018": 10.6}, "Deferred tax assets: -- Share-based compensation": {"2019": 42.4, "2018": 31.4}, "Deferred tax assets: -- Income tax credits": {"2019": 376.5, "2018": 178.4}, "Deferred tax assets: -- Property, plant and equipment": {"2019": 23.6, "2018": 25.7}, "Deferred tax assets: -- Accrued expenses and other": {"2019": 91.4, "2018": 91.2}, "Deferred tax assets: -- Intangible assets": {"2019": 1608.1, "2018": "\u2014"}, "Deferred tax assets: -- Other": {"2019": 12.6, "2018": "\u2014"}, "Deferred tax assets: -- Gross deferred tax assets": {"2019": 2303.5, "2018": 488.2}, "Deferred tax assets: -- Valuation allowances": {"2019": -332.1, "2018": -204.5}, "Deferred tax assets: -- Deferred tax assets, net of valuation allowances": {"2019": 1971.4, "2018": 283.7}, "Deferred tax liabilities: -- Convertible debt": {"2019": -279.3, "2018": -304.4}, "Deferred tax liabilities: -- Intangible assets": {"2019": -721.0, "2018": -66.6}, "Deferred tax liabilities: -- Other": {"2019": "\u2014", "2018": -18.3}, "Deferred tax liabilities: -- Deferred tax liabilities": {"2019": -1000.3, "2018": -389.3}, "Deferred tax liabilities: -- Net deferred tax asset (liability)": {"2019": 971.1, "2018": -105.6}, "Reported as: -- Non-current deferred tax assets": {"2019": 1677.2, "2018": 100.2}, "Reported as: -- Non-current deferred tax liability": {"2019": -706.1, "2018": -205.8}, "Reported as: -- Net deferred tax asset (liability)": {"2019": 971.1, "2018": -105.6}}
net_operating_loss_2019 = df["Deferred tax assets: -- Net operating loss carryforward"]["2019"]
net_operating_loss_2018 = df["Deferred tax assets: -- Net operating loss carryforward"]["2018"]
answer = net_operating_loss_2019 - net_operating_loss_2018