Year	Percent
1990	53.874
1991	53.76
1992	53.679
1993	53.178
1994	52.423
1995	51.151
1996	50.556
1997	49.36
1998	49.116
1999	48.659
2000	49.581
2001	49.977
2002	48.797
2003	48.218
2004	47.48
2005	47.788
2006	46.701
2007	46.437
2008	46.801
2009	47.424
2010	48.272
2011	48.372
2012	48.764
2013	48.778
2014	49.164
2015	48.996
2016	49.02
2017	48.784
2018	48.536
2019	48.271
2020	47.986
2021	47.694
2022	47.394
2023	47.097
2024	46.818
2025	46.569
2026	46.365
2027	46.196
2028	46.047
2029	45.899
2030	45.736