Year	Percent
1990	45.515
1991	41.647
1992	38.05
1993	37.892
1994	38.531
1995	36.33
1996	35.809
1997	35.486
1998	41.63
1999	37.854
2000	37.29
2001	37.204
2002	37.142
2003	37.09
2004	37.027
2005	36.943
2006	36.875
2007	36.78
2008	36.661
2009	36.535
2010	34.759
2011	34.567
2012	32.889
2013	35.691
2014	34.763
2015	34.918
2016	35.195
2017	35.054
2018	34.903
2019	34.744
2020	34.582
2021	34.441
2022	34.299
2023	34.162
2024	34.034
2025	33.919
2026	33.842
2027	33.781
2028	33.728
2029	33.67
2030	33.601