Year	Percent
1990	79.289
1991	78.974
1992	78.372
1993	77.92
1994	77.12
1995	76.661
1996	75.9
1997	75.287
1998	74.754
1999	74.148
2000	73.564
2001	72.861
2002	72.32
2003	71.942
2004	71.648
2005	71.057
2006	70.634
2007	70.278
2008	69.35
2009	68.988
2010	68.083
2011	68.003
2012	68.413
2013	68.841
2014	68.501
2015	68.436
2016	68.343
2017	68.057
2018	67.755
2019	67.376
2020	66.888
2021	66.326
2022	65.658
2023	64.913
2024	64.147
2025	63.404
2026	62.721
2027	62.092
2028	61.517
2029	60.986
2030	60.493