What was the difference between current and non-current assets in 2018?
{"": {"30 June 2019": 0, "30 June 2018": 0}, "Current assets": {"30 June 2019": 447698, "30 June 2018": 464222}, "Non-current assets": {"30 June 2019": 1121500, "30 June 2018": 771702}, "TOTAL ASSETS": {"30 June 2019": 1569198, "30 June 2018": 1235924}, "Current liabilities": {"30 June 2019": 63382, "30 June 2018": 36484}, "Non-current liabilities": {"30 June 2019": 886979, "30 June 2018": 305463}, "TOTAL LIABILITIES": {"30 June 2019": 950361, "30 June 2018": 341947}, "NET ASSETS": {"30 June 2019": 618837, "30 June 2018": 893977}, "Shareholders' equity -- Contributed equity": {"30 June 2019": 905117, "30 June 2018": 904247}, "Shareholders' equity -- Reserves": {"30 June 2019": 6285, "30 June 2018": 6005}, "Shareholders' equity -- Retained earnings": {"30 June 2019": -292565, "30 June 2018": -16275}, "Shareholders' equity -- TOTAL EQUITY": {"30 June 2019": 618837, "30 June 2018": 893977}, "Shareholders' equity -- Profit/(loss) for the year after tax": {"30 June 2019": -266311, "30 June 2018": 6639}, "Shareholders' equity -- Total comprehensive income/(loss) for the year": {"30 June 2019": -261657, "30 June 2018": 6639}}
non_current_assets = df["Non-current assets"]["30 June 2018"]
current_assets = df["Current assets"]["30 June 2018"]
answer = non_current_assets - current_assets