What is the percentage change in the amount of potentially dilutive common shares outstanding of ESPP common stock equivalents from 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}}
espp_common_stock_equivalents_2019 = df["ESPP common stock equivalents"]["2019"]
espp_common_stock_equivalents_2018 = df["ESPP common stock equivalents"]["2018"]
answer = (espp_common_stock_equivalents_2019 - espp_common_stock_equivalents_2018) / espp_common_stock_equivalents_2018 * 100.0