What is the percentage change in publishing between 2018 and 2019?
{"Digital Media": {"2019": 7208.3, "2018": 5857.7, "2017": 4480.8, "% Change 2019 - 2018": 23.0}, "Digital Experience": {"2019": 2670.7, "2018": 1949.3, "2017": 1552.5, "% Change 2019 - 2018": 37.0}, "Publishing": {"2019": 115.5, "2018": 115.2, "2017": 100.6, "% Change 2019 - 2018": "*"}, "Total subscription revenue": {"2019": 9994.5, "2018": 7922.2, "2017": 6133.9, "% Change 2019 - 2018": 26.0}}
publishing_2019 = df["Publishing"]["2019"]
publishing_2018 = df["Publishing"]["2018"]
answer = ( publishing_2019 - publishing_2018 ) / publishing_2018 * 100.0