What was the percentage change in the total directors' remuneration in 2019 from 2018?
{"": {"2019": "\u00a3m", "2018": "\u00a3m"}, "Salaries and short-term benefits": {"2019": 4.1, "2018": 3.7}, "Post-retirement benefits": {"2019": 0.5, "2018": 0.4}, "Share-based payments": {"2019": 1.7, "2018": 1.3}, "Total Directors' remuneration": {"2019": 6.3, "2018": 5.4}}
total_directors_remuneration_2019 = df["Total Directors' remuneration"]["2019"]
total_directors_remuneration_2018 = df["Total Directors' remuneration"]["2018"]
answer = (total_directors_remuneration_2019 - total_directors_remuneration_2018) / total_directors_remuneration_2018 * 100.0