Year	Percent
1990	78.778
1991	79.203
1992	79.475
1993	79.458
1994	79.401
1995	79.292
1996	77.934
1997	77.832
1998	76.701
1999	76.207
2000	75.685
2001	74.205
2002	70.685
2003	70.028
2004	70.486
2005	69.148
2006	70.487
2007	69.979
2008	70.434
2009	70.674
2010	73.427
2011	71.889
2012	73.001
2013	73.264
2014	74.032
2015	74.996
2016	74.541
2017	74.57
2018	74.588
2019	74.598
2020	74.597
2021	74.602
2022	74.614
2023	74.601
2024	74.508
2025	74.305
2026	74.006
2027	73.604
2028	73.159
2029	72.758
2030	72.452