What is the change in net sales in 2018 from 2017?
{"Net sales": {"2019": "$  \u2014", "2018": 262228, "2017": 378152}, "Costs and expenses: -- Cost of sales": {"2019": "\u2014", "2018": 235279, "2017": 342819}, "Costs and expenses: -- Selling, general and administrative expenses": {"2019": "\u2014", "2018": 11365, "2017": 17487}, "Costs and expenses: -- Amortization of purchased intangibles": {"2019": "\u2014", "2018": 1373, "2017": 2752}, "Costs and expenses: -- Restructuring costs": {"2019": "\u2014", "2018": 7, "2017": 208}, "Costs and expenses: -- Other income": {"2019": "\u2014", "2018": -15, "2017": -46}, "Costs and expenses: -- Earnings from discontinued operations before income taxes": {"2019": "\u2014", "2018": 14219, "2017": 14932}, "Costs and expenses: -- Net loss on sale": {"2019": 1423, "2018": 6131, "2017": "\u2014"}, "Costs and expenses: -- Income tax provision": {"2019": "\u2014", "2018": 3845, "2017": 401}, "Costs and expenses: -- Net income (loss) from discontinued operations": {"2019": -1423, "2018": 4243, "2017": 14531}}
net_sales_2018 = df["Net sales"]["2018"]
net_sales_2017 = df["Net sales"]["2017"]
answer = net_sales_2018 - net_sales_2017