Year	Percent
1990	82.958
1991	83.288
1992	83.678
1993	84.125
1994	84.295
1995	84.189
1996	83.686
1997	82.878
1998	82.153
1999	80.796
2000	78.563
2001	77.25
2002	74.884
2003	72.503
2004	69.987
2005	67.306
2006	65.083
2007	62.959
2008	60.97
2009	59.081
2010	57.222
2011	56.499
2012	55.753
2013	55.09
2014	54.38
2015	53.866
2016	53.571
2017	53.316
2018	53.137
2019	52.98
2020	52.817
2021	52.781
2022	52.752
2023	52.716
2024	52.662
2025	52.589
2026	52.607
2027	52.605
2028	52.581
2029	52.542
2030	52.494