Year	Percent
1990	76.446
1991	76.934
1992	77.018
1993	77.561
1994	77.936
1995	77.723
1996	77.462
1997	76.749
1998	76.037
1999	75.334
2000	74.647
2001	74.032
2002	73.44
2003	72.869
2004	72.318
2005	71.783
2006	71.26
2007	70.741
2008	70.226
2009	69.722
2010	70.046
2011	69.488
2012	68.928
2013	70.197
2014	67.406
2015	67.42
2016	67.393
2017	67.339
2018	67.205
2019	66.961
2020	66.592
2021	66.126
2022	65.552
2023	64.892
2024	64.183
2025	63.45
2026	62.721
2027	61.976
2028	61.249
2029	60.585
2030	60.004