Year	Percent
1990	73.195
1991	73.103
1992	71.512
1993	69.905
1994	69.255
1995	69.004
1996	68.763
1997	68.157
1998	68.018
1999	67.697
2000	67.84
2001	68.713
2002	67.938
2003	68.536
2004	68.576
2005	68.583
2006	68.251
2007	67.734
2008	68.186
2009	67.978
2010	67.612
2011	67.929
2012	68.187
2013	67.97
2014	68.075
2015	67.794
2016	68.023
2017	67.7
2018	67.351
2019	66.975
2020	66.575
2021	66.104
2022	65.609
2023	65.108
2024	64.63
2025	64.192
2026	63.761
2027	63.374
2028	63.02
2029	62.683
2030	62.35