What is the ratio of the amount of stock options between 2018 to 2019?
{"Stock options": {"2019": 1687, "2018": 2806, "2017": 569}, "RSUs": {"2019": 2352, "2018": 2580, "2017": 83}, "ESPP common stock equivalents": {"2019": 74, "2018": 71, "2017": "\u2014"}, "ID Checker earnout shares": {"2019": "\u2014", "2018": "\u2014", "2017": 24}, "Total potentially dilutive common shares outstanding": {"2019": 4113, "2018": 5457, "2017": 676}}
stock_options_2018 = df["Stock options"]["2018"]
stock_options_2019 = df["Stock options"]["2019"]
answer = stock_options_2018 / stock_options_2019