Year	Percent
1990	17.431
1991	17.469
1992	17.482
1993	17.446
1994	17.488
1995	17.419
1996	17.337
1997	17.335
1998	17.312
1999	17.288
2000	17.197
2001	17.101
2002	17.041
2003	16.977
2004	16.909
2005	16.848
2006	16.824
2007	16.721
2008	16.714
2009	16.819
2010	16.824
2011	16.733
2012	16.74
2013	16.792
2014	16.784
2015	16.767
2016	16.657
2017	16.632
2018	16.606
2019	16.581
2020	16.555
2021	16.53
2022	16.504
2023	16.479
2024	16.453
2025	16.428
2026	16.402
2027	16.377
2028	16.351
2029	16.326
2030	16.301