Year	Percent
1990	16.99
1991	16.89
1992	17.8
1993	16.32
1994	16.23
1995	16.04
1996	16.31
1997	15.71
1998	14.99
1999	15.11
2000	14.88
2001	14.43
2002	15.12
2003	14.14
2004	13.7
2005	14.07
2006	14.38
2007	16.06
2008	16.39
2009	14.79
2010	14.14
2011	13.55
2012	13.91
2013	14.87
2014	15.63
2015	16.66
2016	16.5
2017	16.494
2018	16.488
2019	16.481
2020	16.475
2021	16.469
2022	16.463
2023	16.457
2024	16.451
2025	16.444
2026	16.438
2027	16.432
2028	16.426
2029	16.42
2030	16.414