What was the change in Net deferred tax assets from 2018 to 2019?
{"Non-current deferred income tax assets": {"2019": 87011, "2018": 64858}, "Non-current deferred income tax liabilities": {"2019": -27785, "2018": -26339}, "Net deferred tax assets": {"2019": 59226, "2018": 38519}}
net_deferred_tax_assets_2019 = df["Net deferred tax assets"]["2019"]
net_deferred_tax_assets_2018 = df["Net deferred tax assets"]["2018"]
answer = net_deferred_tax_assets_2019 - net_deferred_tax_assets_2018