Year	Number
1996	1.53102588653564
1998	1.40700769424438
2000	1.1074413061142
2002	1.22071397304535
2003	1.30756890773773
2004	1.43924069404602
2005	1.47850239276886
2006	1.22095274925232
2007	1.32977032661438
2008	1.37290072441101
2009	1.4649510383606
2010	1.5119845867157
2011	1.60296952724457
2012	1.53973925113678
2013	1.65741109848022
2014	1.64058220386505
2015	1.59465098381042
2016	1.6863489151001
2017	1.8050924539566
2018	1.78418827056885
2019	1.79789400100708
2020	1.69426965713501
2021	1.62860715389252
2022	1.5161395072937