Year	Percent
1990	53.352
1991	53.563
1992	53.992
1993	54.046
1994	55.706
1995	55.662
1996	55.824
1997	55.519
1998	55.699
1999	55.712
2000	55.438
2001	55.025
2002	54.587
2003	54.271
2004	53.993
2005	52.277
2006	50.56
2007	48.798
2008	46.984
2009	45.104
2010	44.433
2011	44.85
2012	43.49
2013	43.889
2014	43.361
2015	46.568
2016	45.26
2017	45.048
2018	44.873
2019	44.685
2020	44.453
2021	44.187
2022	43.878
2023	43.544
2024	43.218
2025	42.913
2026	42.625
2027	42.344
2028	42.045
2029	41.689
2030	41.25