Year	Percent
1990	73.198
1991	73.083
1992	72.971
1993	72.852
1994	72.707
1995	72.52
1996	72.297
1997	72.033
1998	71.726
1999	71.383
2000	71.01
2001	70.203
2002	69.329
2003	68.423
2004	67.553
2005	66.766
2006	66.065
2007	65.464
2008	64.924
2009	64.376
2010	63.777
2011	63.533
2012	63.296
2013	63.059
2014	62.775
2015	62.436
2016	62.034
2017	61.488
2018	60.871
2019	60.221
2020	59.569
2021	58.93
2022	58.294
2023	57.659
2024	57.018
2025	56.369
2026	55.742
2027	55.121
2028	54.508
2029	53.899
2030	53.292