Year	Number
1996	1.9805189371109
1998	2.05252122879028
2000	2.0724573135376
2002	2.00263667106628
2003	1.98295390605927
2004	1.91091167926788
2005	1.89147984981537
2006	1.78294026851654
2007	1.732870221138
2008	1.66890430450439
2009	1.62388980388641
2010	1.60567390918732
2011	1.61486351490021
2012	1.66546046733856
2013	1.7188925743103
2014	1.74663364887238
2015	1.83159017562866
2016	1.8506041765213
2017	1.81362438201904
2018	1.8065721988678
2019	1.74877238273621
2020	1.6600604057312
2021	1.64092922210693
2022	1.62015616893768