| Year | Value | | 2021 | 15.10031106628 | | 2020 | 12.642711719659 | | 2019 | 22.875475464151 | | 2018 | 25.086277175752 | | 2017 | 20.059804785784 | | 2016 | 14.977122088012 | | 2015 | 36.054508351309 | | 2014 | 62.79066643768 | | 2013 | 93.865034103364 | | 2012 | 147.6401955392 | | 2011 | 135.48445054102 | | 2010 | 110.17258804732 |
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