Year	Percent
1990	92.3
1991	91.466
1992	91.165
1993	90.208
1994	90.571
1995	91.256
1996	91.418
1997	92.257
1998	92.261
1999	91.824
2000	91.711
2001	91.516
2002	91.413
2003	89.744
2004	89.671
2005	89.904
2006	90.472
2007	90.832
2008	91.29
2009	90.834
2010	90.132
2011	89.623
2012	89.578
2013	89.049
2014	89.295
2015	89.027
2016	88.796
2017	88.72
2018	88.647
2019	88.579
2020	88.518
2021	88.462
2022	88.41
2023	88.362
2024	88.317
2025	88.275
2026	88.235
2027	88.197
2028	88.158
2029	88.115
2030	88.065