Year	%
1980	8.96865719474416
1981	8.96865719474416
1982	8.96865719474416
1983	9.49182886443757
1984	10.762388633693
1985	10.8371274436492
1986	11.2108214934302
1987	11.2108214934302
1988	10.7997580386711
1989	11.2108214934302
1990	11.5471461382331
1991	11.1853680321861
1992	11.2968130358593
1993	11.9218397449356
1994	11.7331882751291
1995	11.0656845250305
1996	11.2251135234881
1997	11.2905743211062
1998	11.3070990509593
1999	11.5463818610657
2000	11.4644838851929
2001	11.6261472887473
2002	11.5626385220607
2003	11.8323845219297
2004	9.69262522955306
2005	9.58412535234746
2006	9.73167779068317
2007	9.61258286342562
2008	9.52441609219704
2009	9.18656075402981
2010	9.17183767616861
2011	9.13637805336276
2012	9.41440897330206
2013	9.43978132892116
2014	9.14600845222647
2015	9.30275
2016	9.1175
2017	8.7525
2018	8.48572125
2019	8.35136941666667
2020	7.99094591666667
2021	7.650287
2022	7.3919885
2023	7.16251175