What was the percentage change in the diluted Pro forma common shares between 2017 and 2018?
{"Pro forma revenues (3)": {"2018 (1)": 1217655.0, "2017 (2)": 1060777.0}, "Pro forma net income from continuing operations available to common stockholders (3)": {"2018 (1)": 51975.0, "2017 (2)": 226086.0}, "Pro forma earnings per common share - basic (3)": {"2018 (1)": 0.98, "2017 (2)": 4.86}, "Pro forma earnings per common share - diluted (3)": {"2018 (1)": 0.89, "2017 (2)": 4.08}, "Pro forma common shares - basic": {"2018 (1)": 52798.0, "2017 (2)": 46552.0}, "Pro forma common shares - diluted": {"2018 (1)": 58640.0, "2017 (2)": 55389.0}}
pro_forma_common_shares_2018 = df["Pro forma common shares - diluted"]["2018 (1)"]
pro_forma_common_shares_2017 = df["Pro forma common shares - diluted"]["2017 (2)"]
answer = (pro_forma_common_shares_2018 - pro_forma_common_shares_2017) / pro_forma_common_shares_2017 * 100.0