| Year | Value | | 2024 | 2.076553879542 | | 2023 | 1.4950681651508 | | 2022 | 5.1798084796706 | | 2021 | 1.181917753398 | | 2020 | 1.7774078380618 | | 2019 | 3.3192537270383 | | 2018 | 0.14797084987712 | | 2017 | 0.56811211708472 | | 2016 | 2.7384120873876 | | 2015 | 0.84738973397199 | | 2014 | 1.3418649434016 | | 2013 | 2.7060324287218 | | 2012 | 3.7312095075689 | | 2011 | 5.0687139477798 |
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