What was the 2019 percentage change in total contractual cash flows of total non-derivatives?
{"2019": {"Within 12 months": 0, "Between 1 and 5 years": 0, "Over 5 years": 0, "Total contractual cash flows": 0, "Carrying amount": 0}, "Trade payables": {"Within 12 months": 44840, "Between 1 and 5 years": "-", "Over 5 years": "-", "Total contractual cash flows": 44840, "Carrying amount": 44840}, "Unsecured notes": {"Within 12 months": 46634, "Between 1 and 5 years": 900046, "Over 5 years": "-", "Total contractual cash flows": 946680, "Carrying amount": 793849}, "Lease liabilities": {"Within 12 months": 5008, "Between 1 and 5 years": 26709, "Over 5 years": 167214, "Total contractual cash flows": 198931, "Carrying amount": 73328}, "Total non-derivatives": {"Within 12 months": 96482, "Between 1 and 5 years": 926755, "Over 5 years": 167214, "Total contractual cash flows": 1190451, "Carrying amount": 912017}, "2018 -- Trade payables": {"Within 12 months": 27640, "Between 1 and 5 years": "-", "Over 5 years": "-", "Total contractual cash flows": 27640, "Carrying amount": 27640}, "2018 -- Unsecured notes": {"Within 12 months": 18750, "Between 1 and 5 years": 342000, "Over 5 years": "-", "Total contractual cash flows": 360750, "Carrying amount": 296912}, "2018 -- Lease liabilities": {"Within 12 months": 641, "Between 1 and 5 years": 2565, "Over 5 years": 5451, "Total contractual cash flows": 8657, "Carrying amount": 6042}, "2018 -- Total non-derivatives": {"Within 12 months": 47031, "Between 1 and 5 years": 344565, "Over 5 years": 5451, "Total contractual cash flows": 397047, "Carrying amount": 330594}}
total_nonderivatives_total_contractual_cash_flows_2019 = df["Total non-derivatives"]["Total contractual cash flows"]
total_nonderivatives_total_contractual_cash_flows_2018 = df["2018 -- Total non-derivatives"]["Total contractual cash flows"]
answer = ( total_nonderivatives_total_contractual_cash_flows_2019 - total_nonderivatives_total_contractual_cash_flows_2018 ) / total_nonderivatives_total_contractual_cash_flows_2018 * 100.0