Year	Percent
1990	62.391
1991	61.515
1992	60.975
1993	60.483
1994	59.786
1995	58.745
1996	57.955
1997	56.894
1998	56.3
1999	54.516
2000	52.72
2001	52.638
2002	52.557
2003	52.475
2004	52.393
2005	52.312
2006	52.23
2007	49.407
2008	46.588
2009	43.79
2010	43.23
2011	45.395
2012	47.578
2013	49.77
2014	49.465
2015	49.441
2016	49.192
2017	48.72
2018	48.247
2019	47.775
2020	47.302
2021	46.83
2022	46.357
2023	45.885
2024	45.412
2025	44.94
2026	44.467
2027	43.995
2028	43.522
2029	43.05
2030	42.577