Year	Number
1996	1.25185739994049
1998	1.45350337028503
2000	1.63705730438232
2002	1.54408168792725
2003	1.6510945558548
2004	1.75563025474548
2005	1.66645479202271
2006	1.62847626209259
2007	1.46457493305206
2008	1.57403433322906
2009	1.47705447673798
2010	1.46266102790833
2011	1.39230680465698
2012	1.37338125705719
2013	1.48261678218842
2014	1.41354477405548
2015	1.41785860061646
2016	1.38138175010681
2017	1.30881631374359
2018	1.4197963476181
2019	1.33828783035278
2020	1.2046355009079
2021	1.23061394691467
2022	1.165806889534