Year	Number
1996	1.43329954147339
1998	1.34284746646881
2000	1.36650443077087
2002	1.37745249271393
2003	1.47829031944275
2004	1.44026613235474
2005	1.42076218128204
2006	1.34239435195923
2007	1.36077105998993
2008	1.32498848438263
2009	1.3466922044754
2010	1.36068689823151
2011	1.32516324520111
2012	1.34942185878754
2013	1.3730456829071
2014	1.36636698246002
2015	1.38745987415314
2016	1.37702023983002
2017	1.33848917484283
2018	1.33021223545074
2019	1.3083484172821
2020	1.27844524383545
2021	1.271479845047
2022	1.29260873794556