What is the Number of shares available, end of year expressed as a percentage of Number of shares available, beginning of year for 2019? 
{"Number of shares available, beginning of year": {"2019": 4489347, "2018": 3668954, "2017": 5385870}, "Newly Registered Shares under Omnibus Incentive Plan": {"2019": "\u2014", "2018": 2199114, "2017": "\u2014"}, "Restricted stock shares issued for new awards(1)": {"2019": "\u2014", "2018": -571438, "2017": -480283}, "Restricted stock shares forfeited(1)": {"2019": 105960, "2018": 91542, "2017": 184235}, "Restricted stock units awarded": {"2019": -819808, "2018": -219923, "2017": -351946}, "Restricted stock units forfeited": {"2019": 96534, "2018": 64122, "2017": 288801}, "Shares issued for 2014 Special PSU Awards": {"2019": "\u2014", "2018": -658783, "2017": -749653}, "Shares issued for 2015 Three-Year PSU Awards": {"2019": "\u2014", "2018": -129139, "2017": "\u2014"}, "Shares issued for 2014 Three-Year PSU Awards": {"2019": "\u2014", "2018": "\u2014", "2017": -636723}, "Restricted stock units awarded for SLO Awards": {"2019": -46195, "2018": -23478, "2017": -44254}, "SLO units forfeited": {"2019": 1580, "2018": 817, "2017": 3639}, "Director shares granted and issued": {"2019": -22015, "2018": -10560, "2017": -15491}, "Director units granted and deferred(2)": {"2019": -6262, "2018": -16505, "2017": -17008}, "Shares withheld for taxes(3)": {"2019": 249368, "2018": 94624, "2017": 101767}, "Number of shares available, end of year(4)": {"2019": 4048509, "2018": 4489347, "2017": 3668954}}
num_shares_end_of_year_4_2019 = df["Number of shares available, end of year(4)"]["2019"]
num_shares_beginning_of_year_2019 = df["Number of shares available, beginning of year"]["2019"]
answer = num_shares_end_of_year_4_2019 / num_shares_beginning_of_year_2019 * 100.0