Year	Percent
1990	38.247
1991	39.056
1992	39.736
1993	40.451
1994	41.415
1995	42.794
1996	43.245
1997	43.689
1998	43.913
1999	44.116
2000	44.863
2001	45.596
2002	46.308
2003	46.873
2004	47.119
2005	47.951
2006	46.619
2007	47.501
2008	48.631
2009	49.774
2010	49.113
2011	46.677
2012	48.424
2013	50.658
2014	50.857
2015	51.817
2016	52.778
2017	52.8
2018	52.821
2019	52.834
2020	52.835
2021	52.837
2022	52.832
2023	52.82
2024	52.801
2025	52.772
2026	52.747
2027	52.717
2028	52.683
2029	52.651
2030	52.623