What is the percentage change in the beginning balance of the company's liability insurance between 2018 and 2019?
{"Beginning balance": {"2019": 1.6, "2018": 1.5}, "Charged to expense": {"2019": 5.4, "2018": 5.8}, "Payments": {"2019": -5.5, "2018": -5.7}, "Ending balance": {"2019": 1.5, "2018": 1.6}}
beginning_balance_2019 = df["Beginning balance"]["2019"]
beginning_balance_2018 = df["Beginning balance"]["2018"]
answer = ( beginning_balance_2019 - beginning_balance_2018 ) / beginning_balance_2018 * 100.0