Year	Percent
1990	81.764
1991	81.742
1992	80.169
1993	78.459
1994	77.667
1995	77.323
1996	77.092
1997	76.552
1998	76.422
1999	75.974
2000	76.104
2001	77.056
2002	76.15
2003	76.729
2004	76.711
2005	76.648
2006	76.397
2007	75.949
2008	76.383
2009	76.29
2010	76.01
2011	76.57
2012	77.155
2013	77.213
2014	77.596
2015	77.531
2016	78.357
2017	78.508
2018	78.641
2019	78.728
2020	78.751
2021	78.713
2022	78.603
2023	78.444
2024	78.279
2025	78.133
2026	78.003
2027	77.894
2028	77.787
2029	77.651
2030	77.469