Year	Percent
1990	56.896
1991	56.865
1992	56.827
1993	56.762
1994	56.505
1995	56.358
1996	56.071
1997	55.855
1998	55.539
1999	55.285
2000	55.145
2001	55.133
2002	55.188
2003	55.281
2004	55.464
2005	54.406
2006	53.387
2007	52.359
2008	51.302
2009	50.193
2010	48.971
2011	49.445
2012	47.357
2013	48.424
2014	47.973
2015	50.67
2016	49.202
2017	49.315
2018	49.407
2019	49.45
2020	49.428
2021	49.333
2022	49.169
2023	48.96
2024	48.743
2025	48.54
2026	48.341
2027	48.152
2028	47.968
2029	47.778
2030	47.577