Year | Value | 2021 | 31.263906555231 | 2020 | 33.461768260177 | 2019 | 26.581873783843 | 2018 | 25.169066550339 | 2017 | 25.744551753517 | 2016 | 25.308198912241 | 2015 | 24.421183185115 | 2014 | 23.137554027698 | 2013 | 20.718279396317 | 2012 | 21.554982341294 | 2011 | 21.887582406823 | 2010 | 22.428465675234 | 2009 | 23.304776799733 | 2008 | 18.486812174218 | 1998 | 95.937303786616 |
|