Year	Percent
1990	53.59
1991	55.781
1992	56.097
1993	55.281
1994	54.535
1995	53.502
1996	52.907
1997	53.561
1998	52.978
1999	52.165
2000	51.718
2001	51.095
2002	50.679
2003	49.759
2004	48.878
2005	48.051
2006	47.389
2007	46.803
2008	46.269
2009	44.945
2010	45.693
2011	47.104
2012	48.806
2013	44.65
2014	44.789
2015	47.676
2016	47.439
2017	47.218
2018	47.035
2019	46.869
2020	46.703
2021	46.595
2022	46.501
2023	46.393
2024	46.236
2025	46.008
2026	45.771
2027	45.467
2028	45.113
2029	44.739
2030	44.366