Year	%
1980	3.77486901230616
1981	3.77486901230616
1982	3.77486901230616
1983	4.08944142999834
1984	4.08944142999834
1985	4.11565579813935
1986	4.08944142999834
1987	4.14187016628037
1988	4.7185862653827
1989	4.66615752910067
1990	4.7185862653827
1991	4.52406261716071
1992	4.34772277562923
1993	4.39210350152686
1994	3.9914226821924
1995	4.52162161940397
1996	4.26598991133415
1997	4.26937956943307
1998	4.2183034547814
1999	4.31362890850767
2000	4.32232209770158
2001	4.226800433103
2002	4.01062105825657
2003	4.49276706162147
2004	4.54373894239835
2005	4.50966193235682
2006	4.56113925921092
2007	4.59570719231265
2008	4.5493046014204
2009	4.5906545096741
2010	4.59337940425058
2011	4.46535566484007
2012	4.27461850682493
2013	3.7362458644477
2014	3.18368773945204
2015	2.723
2016	2.5
2017	2.2675
2018	2.07676683333333
2019	2.00926616666667
2020	2.22423766666667
2021	2.255278
2022	2.0531835
2023	1.999894