Year	Percent
1991	40.491
1992	40.091
1993	39.694
1994	39.485
1995	39.633
1996	39.858
1997	40.942
1998	41.392
1999	33.994
2000	34.536
2001	40.671
2002	37.981
2003	35.082
2004	31.584
2005	32.49
2006	30.635
2007	32.785
2008	35.198
2009	39.396
2010	42.462
2011	44.992
2012	44.633
2013	45.39
2014	46.503
2015	48.151
2016	66.317
2017	65.621
2018	65.601
2019	65.393
2020	65.257
2021	64.88
2022	64.636