What was the percentage change in the Initial obligation from transfer of Charged-Off Receivables between 2018 and 2019?
{"Beginning balance": {"2019": 3016, "2018": 2071, "2017": "$\u2014"}, "Initial obligation from transfer of Charged-Off Receivables(1)": {"2019": 2705, "2018": 2461, "2017": 2379}, "Fair value changes recognized in other gains (losses), net(2)": {"2019": -1925, "2018": -1516, "2017": -308}, "Ending balance": {"2019": 3796, "2018": 3016, "2017": 2071}}
initial_obligation_2019 = df["Initial obligation from transfer of Charged-Off Receivables(1)"]["2019"]
initial_obligation_2018 = df["Initial obligation from transfer of Charged-Off Receivables(1)"]["2018"]
answer = (initial_obligation_2019 - initial_obligation_2018) / initial_obligation_2018 * 100.0