Year	Percent
1990	75.018
1991	75.647
1992	76.044
1993	75.891
1994	75.635
1995	75.242
1996	73.514
1997	72.899
1998	72.074
1999	71.787
2000	71.074
2001	69.565
2002	64.353
2003	62.961
2004	62.58
2005	61.17
2006	62.212
2007	62.196
2008	62.332
2009	62.274
2010	64.308
2011	62.768
2012	63.578
2013	63.537
2014	63.94
2015	64.226
2016	63.461
2017	63.133
2018	62.794
2019	62.459
2020	62.139
2021	61.767
2022	61.418
2023	61.089
2024	60.774
2025	60.464
2026	60.096
2027	59.744
2028	59.392
2029	59.019
2030	58.617