Year	Percent
1990	45.568
1991	45.547
1992	45.603
1993	45.618
1994	45.659
1995	45.673
1996	45.718
1997	45.65
1998	45.571
1999	45.478
2000	45.373
2001	45.275
2002	45.165
2003	45.042
2004	44.902
2005	44.742
2006	44.622
2007	44.512
2008	45.668
2009	46.837
2010	48.017
2011	49.17
2012	50.324
2013	51.481
2014	52.643
2015	52.763
2016	52.807
2017	53.059
2018	53.314
2019	53.561
2020	53.795
2021	54.019
2022	54.231
2023	54.432
2024	54.628
2025	54.823
2026	55.018
2027	55.212
2028	55.407
2029	55.607
2030	55.814