Year	Percent
1990	46.153
1991	46.436
1992	46.735
1993	46.951
1994	47.238
1995	47.684
1996	47.904
1997	48.363
1998	48.945
1999	49.415
2000	49.8
2001	50.191
2002	50.634
2003	50.964
2004	51.438
2005	53.358
2006	55.268
2007	53.821
2008	52.368
2009	50.909
2010	49.448
2011	47.984
2012	55.068
2013	49.355
2014	49.738
2015	47.775
2016	48.852
2017	48.836
2018	48.817
2019	48.794
2020	48.769
2021	48.742
2022	48.714
2023	48.685
2024	48.656
2025	48.628
2026	48.601
2027	48.574
2028	48.55
2029	48.532
2030	48.522