What was the percentage change in number of rights granted?
{"Performance rights issued and outstanding at 30 June 2019 -- Grant Date": {"Vesting Date1": 1, "Fair Value per Right $": "Fair Value per Right $", "Rights Granted": "Rights Granted", "No. of Rights at 30/6/2019": 30}, "Performance rights issued and outstanding at 30 June 2019 -- 2 Jul 2017": {"Vesting Date1": 31.0, "Fair Value per Right $": 3.815, "Rights Granted": 355316.0, "No. of Rights at 30/6/2019": 355316.0}, "Performance rights issued and outstanding at 30 June 2019 -- 2 Jul 2018": {"Vesting Date1": 31.0, "Fair Value per Right $": 3.01, "Rights Granted": 530652.0, "No. of Rights at 30/6/2019": 530652.0}, "Performance rights issued and outstanding at 30 June 2019 -- Total": {"Vesting Date1": "", "Fair Value per Right $": "", "Rights Granted": 885968, "No. of Rights at 30/6/2019": 885968}}
rights_2018 = df["Performance rights issued and outstanding at 30 June 2019 -- 2 Jul 2018"]["Rights Granted"]
rights_2017 = df["Performance rights issued and outstanding at 30 June 2019 -- 2 Jul 2017"]["Rights Granted"]
answer = (rights_2018 - rights_2017) / rights_2017 * 100.0