Year	Percent
1990	17.945
1991	18.424
1992	18.206
1993	17.97
1994	18.438
1995	17.253
1996	17.505
1997	18.419
1998	17.939
1999	17.583
2000	17.5
2001	18.39
2002	19.42
2003	21.8
2004	18.34
2005	19.57
2006	16.99
2007	18.39
2008	21.45
2009	18.97
2010	20.45
2011	17.49
2012	14.97
2013	13.28
2014	11.48
2015	10.71
2016	10.58
2017	10.417
2018	10.254
2019	10.091
2020	9.929
2021	9.766
2022	9.603
2023	9.44
2024	9.277
2025	9.114
2026	8.952
2027	8.789
2028	8.626
2029	8.463
2030	8.3