Year	Number
1996	1.8005645275116
1998	1.61811804771423
2000	1.73217022418976
2002	1.65919864177704
2003	1.77327883243561
2004	1.98494184017181
2005	1.74618124961853
2006	1.70789933204651
2007	1.81895518302917
2008	1.78476786613464
2009	1.70196378231049
2010	1.76339137554169
2011	1.69013810157776
2012	1.61314845085144
2013	1.63284754753113
2014	1.60136985778809
2015	1.53417503833771
2016	1.5333389043808
2017	1.49827075004578
2018	1.55606377124786
2019	1.53876042366028
2020	1.57377552986145
2021	1.47399628162384
2022	1.52887463569641