What was the change in Non-current minimum lease payments receivable between 2018 and 2019?
{"Current minimum lease payments receivable(1)": {"December 31, 2019": 1201, "December 31, 2018": 11339}, "Non-current minimum lease payments receivable(2)": {"December 31, 2019": 889, "December 31, 2018": 1670}, "Total minimum lease payments receivable": {"December 31, 2019": 2090, "December 31, 2018": 13009}, "Less: Current unearned revenue(1)": {"December 31, 2019": 365, "December 31, 2018": 631}, "Less: Non-current unearned revenue(2)": {"December 31, 2019": 163, "December 31, 2018": 473}, "Net investment in sales-type leases": {"December 31, 2019": 1562, "December 31, 2018": 11905}}
non_current_min_lease_2019 = df["Non-current minimum lease payments receivable(2)"]["December 31, 2019"]
non_current_min_lease_2018 = df["Non-current minimum lease payments receivable(2)"]["December 31, 2018"]
answer = non_current_min_lease_2019 - non_current_min_lease_2018