What was the percentage change in non-cash impairment charges in 2019 from 2018?
{"Lease obligations and facility exit costs (1)": {"Americas 2018 Exit Plan": 7073, "Americas 2019 Exit Plan": "$\u2014"}, "Severance and related costs (2)": {"Americas 2018 Exit Plan": 3426, "Americas 2019 Exit Plan": 191}, "Severance and related costs (1)": {"Americas 2018 Exit Plan": 1037, "Americas 2019 Exit Plan": 2155}, "Non-cash impairment charges": {"Americas 2018 Exit Plan": 5875, "Americas 2019 Exit Plan": 1582}, "Other non-cash charges": {"Americas 2018 Exit Plan": "\u2014", "Americas 2019 Exit Plan": 244}, "": {"Americas 2018 Exit Plan": 17411, "Americas 2019 Exit Plan": 4172}}
noncash_impairment_charges_2019 = df["Non-cash impairment charges"]["Americas 2019 Exit Plan"]
noncash_impairment_charges_2018 = df["Non-cash impairment charges"]["Americas 2018 Exit Plan"]
answer = (noncash_impairment_charges_2019 - noncash_impairment_charges_2018) / noncash_impairment_charges_2018 * 100.0