What was the change in Diluted weighted-average common shares outstanding between 2018 and 2019?
{"Income from continuing operations": {"2019": 56495.0, "2018": 147149.0, "2017": 136101.0}, "Income from continuing operations attributable to noncontrolling interest": {"2019": 34.0, "2018": 86.0, "2017": "\u2014"}, "Income from continuing operations attributable to Advanced Energy Industries, Inc.": {"2019": 56461.0, "2018": 147063.0, "2017": 136101.0}, "Basic weighted-average common shares outstanding": {"2019": 38281.0, "2018": 39081.0, "2017": 39754.0}, "Assumed exercise of dilutive stock options and restricted stock units": {"2019": 214.0, "2018": 271.0, "2017": 422.0}, "Diluted weighted-average common shares outstanding": {"2019": 38495.0, "2018": 39352.0, "2017": 40176.0}, "Continuing operations: -- Basic earnings per share": {"2019": 1.47, "2018": 3.76, "2017": 3.42}, "Continuing operations: -- Diluted earnings per share": {"2019": 1.47, "2018": 3.74, "2017": 3.39}}
diluted_weightedaverage_common_shares_outstanding_2019 = df["Diluted weighted-average common shares outstanding"]["2019"]
diluted_weightedaverage_common_shares_outstanding_2018 = df["Diluted weighted-average common shares outstanding"]["2018"]
answer = diluted_weightedaverage_common_shares_outstanding_2019 - diluted_weightedaverage_common_shares_outstanding_2018