Year	Percent
1990	56.143
1991	55.919
1992	55.542
1993	54.807
1994	53.44
1995	53.073
1996	53
1997	53.128
1998	53.389
1999	53.643
2000	53.759
2001	53.668
2002	53.509
2003	53.178
2004	52.928
2005	52.79
2006	52.746
2007	52.789
2008	52.921
2009	53.001
2010	53.032
2011	53.063
2012	53.045
2013	52.952
2014	52.865
2015	52.777
2016	52.654
2017	52.635
2018	52.617
2019	52.598
2020	52.58
2021	52.561
2022	52.542
2023	52.524
2024	52.505
2025	52.486
2026	52.468
2027	52.449
2028	52.43
2029	52.412
2030	52.393