What is the increase / (decrease) in the Integrated device manufacturers from 2017 to 2018?
{"": {"2017": "%", "2018": "%", "2019": "%"}, "Fabless design companies": {"2017": 91.0, "2018": 92.4, "2019": 91.3}, "Integrated device manufacturers": {"2017": 9.0, "2018": 7.6, "2019": 8.7}, "Total": {"2017": 100.0, "2018": 100.0, "2019": 100.0}}
integrated_device_manufacturers_2018 = df["Integrated device manufacturers"]["2018"]
integrated_device_manufacturers_2017 = df["Integrated device manufacturers"]["2017"]
answer = integrated_device_manufacturers_2018 - integrated_device_manufacturers_2017