Year	Percent
1990	75.589
1991	75.889
1992	75.854
1993	76.065
1994	75.891
1995	75.714
1996	75.304
1997	74.92
1998	74.541
1999	74.14
2000	73.732
2001	73.348
2002	72.975
2003	72.611
2004	72.255
2005	71.908
2006	71.587
2007	71.27
2008	70.982
2009	70.756
2010	70.609
2011	70.252
2012	69.954
2013	69.682
2014	69.394
2015	70.486
2016	71.214
2017	71.324
2018	71.412
2019	71.475
2020	71.511
2021	71.53
2022	71.521
2023	71.486
2024	71.429
2025	71.352
2026	71.264
2027	71.159
2028	71.043
2029	70.923
2030	70.805