Year Number 1996 0.981364369392395 1998 0.930068552494049 2000 1.03310573101044 2002 0.672591328620911 2003 0.27125072479248 2004 0.140847533941269 2005 0.124187760055065 2006 0.667080104351044 2007 0.574654936790466 2008 0.492879867553711 2009 0.121949501335621 2010 0.411818206310272 2011 0.351707607507706 2012 0.40227073431015 2013 0.48620143532753 2014 0.415347635746002 2015 0.503706395626068 2016 0.347932636737823 2017 0.380708187818527 2018 0.07756457477808 2019 0.527470409870148 2020 0.481457024812698 2021 0.4898921251297 2022 0.503939092159271