What was the percentage change in Beginning balance in 2019 from 2018?
{"Beginning balance": {"2019": 40220, "2018": 36149, "2017": 15949}, "Additions related to current period sales": {"2019": 52271, "2018": 58865, "2017": 41365}, "Warranty costs incurred in the current period": {"2019": -54538, "2018": -51935, "2017": -31825}, "Accruals resulting from acquisitions": {"2019": 21, "2018": 179, "2017": 14314}, "Adjustments to accruals related to foreign exchange and other": {"2019": -1514, "2018": -3038, "2017": -3654}, "Ending balance": {"2019": 36460, "2018": 40220, "2017": 36149}}
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