What was the percentage change in the carrying value in total financial assets from 2018 to 2019?
{"": {"2019 Fair value": "\u00a3m", "2019 Carrying value": "\u00a3m", "2018 Carrying value": "\u00a3m", "2018 Fair value": "\u00a3m"}, "Financial assets: -- Cash and cash equivalents": {"2019 Fair value": 168.5, "2019 Carrying value": 168.5, "2018 Carrying value": 187.1, "2018 Fair value": 187.1}, "Financial assets: -- Trade, other receivables and contract assets": {"2019 Fair value": 263.4, "2019 Carrying value": 263.4, "2018 Carrying value": 264.9, "2018 Fair value": 264.9}, "Financial assets: -- Total financial assets": {"2019 Fair value": 431.9, "2019 Carrying value": 431.9, "2018 Carrying value": 452.0, "2018 Fair value": 452.0}}
total_financial_assets_2019 = df["Financial assets: -- Total financial assets"]["2019 Fair value"]
total_financial_assets_2018 = df["Financial assets: -- Total financial assets"]["2018 Carrying value"]
answer = (total_financial_assets_2019 - total_financial_assets_2018) / total_financial_assets_2018 * 100.0