Year	Percent
1990	77.572
1991	77.264
1992	77.773
1993	77.623
1994	76.954
1995	76.725
1996	76.029
1997	75.7
1998	74.908
1999	74.1
2000	74.546
2001	74.987
2002	75.423
2003	75.854
2004	76.28
2005	75.774
2006	75.262
2007	74.742
2008	74.214
2009	73.68
2010	73.138
2011	72.59
2012	72.152
2013	72.039
2014	71.955
2015	72.035
2016	72.079
2017	71.874
2018	71.67
2019	71.466
2020	71.261
2021	71.057
2022	70.853
2023	70.648
2024	70.444
2025	70.239
2026	70.035
2027	69.831
2028	69.626
2029	69.422
2030	69.218