Year	Percent
1991	48.896
1992	48.639
1993	47.985
1994	47.813
1995	49.904
1996	50.474
1997	49.87
1998	50.087
1999	48.672
2000	46.648
2001	44.987
2002	45.718
2003	48.043
2004	49.714
2005	50.621
2006	53.134
2007	55.987
2008	58.481
2009	56.756
2010	53.064
2011	51.093
2012	50.767
2013	51.306
2014	52.69
2015	54.27
2016	54.758
2017	55.773
2018	56.488
2019	56.721
2020	56.877
2021	56.873
2022	56.835