Year	Percent
1990	83.299
1991	83.461
1992	83.421
1993	83.496
1994	83.4
1995	83.586
1996	83.732
1997	83.844
1998	83.95
1999	82.364
2000	80.657
2001	78.828
2002	76.875
2003	74.799
2004	72.604
2005	70.293
2006	67.874
2007	65.355
2008	62.747
2009	60.062
2010	57.316
2011	54.523
2012	51.702
2013	48.87
2014	48.779
2015	48.687
2016	48.576
2017	48.33
2018	48.085
2019	47.839
2020	47.593
2021	47.348
2022	47.102
2023	46.857
2024	46.611
2025	46.366
2026	46.12
2027	45.874
2028	45.629
2029	45.383
2030	45.138