Year	Percent
1990	11.82
1991	11
1992	11.75
1993	10.95
1994	11.8
1995	11.69
1996	11.52
1997	10.73
1998	9.51
1999	9.03
2000	8.53
2001	7.89
2002	7.85
2003	8.1
2004	6.88
2005	6.99
2006	7.3
2007	7.12
2008	7.15
2009	6.77
2010	6.39
2011	5.61
2012	4.55
2013	4.31
2014	4.52
2015	4.37
2016	4.33
2017	4.165
2018	3.999
2019	3.834
2020	3.668
2021	3.503
2022	3.337
2023	3.172
2024	3.006
2025	2.841
2026	2.675
2027	2.51
2028	2.344
2029	2.179
2030	2.013