Year	Percent
1990	54.572
1991	54.38
1992	54.213
1993	54.066
1994	53.923
1995	53.782
1996	53.622
1997	53.487
1998	53.361
1999	55.044
2000	54.793
2001	53.148
2002	52.106
2003	54.881
2004	51.416
2005	50.602
2006	50.134
2007	50.176
2008	50.539
2009	52.063
2010	52.546
2011	53.107
2012	53.627
2013	53.256
2014	54.077
2015	54.546
2016	55.859
2017	55.906
2018	55.926
2019	55.891
2020	55.779
2021	55.587
2022	55.322
2023	54.996
2024	54.631
2025	54.245
2026	53.822
2027	53.386
2028	52.95
2029	52.532
2030	52.147