Why is the firm's EBITDA margin increasing given that sales are decreasing? Please be specific. Ratios Sales Growth rate EBITDA Margin SG&A Margin Net Profit Margin 2017 21.5% 34% 6.2% 23.1% 2018 16.5 % 38.5% 6.1% 18.75% 2019 12.5% 40.06% 6.15% 17.1%