Year	Percent
1990	60.356
1991	61.743
1992	60.916
1993	61.754
1994	61.045
1995	60.307
1996	61.649
1997	62.5
1998	62.584
1999	60.521
2000	59.463
2001	59.312
2002	59.148
2003	59.054
2004	59.163
2005	59.122
2006	58.494
2007	57.711
2008	56.597
2009	55.812
2010	55.014
2011	54.264
2012	53.513
2013	52.75
2014	51.973
2015	51.193
2016	51.179
2017	51.028
2018	50.872
2019	50.698
2020	50.504
2021	50.331
2022	50.144
2023	49.939
2024	49.721
2025	49.497
2026	49.304
2027	49.111
2028	48.902
2029	48.662
2030	48.387