What was the percentage change in total inventories from 2018 to 2019?
{"": {"2019": "\u00a3m", "2018": "\u00a3m"}, "Raw materials, consumables and components": {"2019": 72.2, "2018": 53.0}, "Work in progress": {"2019": 25.5, "2018": 25.7}, "Finished goods and goods for resale": {"2019": 88.2, "2018": 81.9}, "Total inventories": {"2019": 185.9, "2018": 160.6}}
total_inventories_2019 = df["Total inventories"]["2019"]
total_inventories_2018 = df["Total inventories"]["2018"]
answer = ( total_inventories_2019 - total_inventories_2018 ) / total_inventories_2018 * 100.0