Year	Percent
1991	40.845
1992	40.657
1993	40.469
1994	40.378
1995	40.487
1996	40.771
1997	41.574
1998	41.893
1999	36.901
2000	37.157
2001	43.409
2002	41.111
2003	36.832
2004	31.271
2005	31.413
2006	29.792
2007	31.596
2008	33.241
2009	36.576
2010	38.701
2011	42.277
2012	43.958
2013	46.133
2014	46.805
2015	47.625
2016	58.724
2017	57.131
2018	57.05
2019	56.497
2020	56.035
2021	55.179
2022	54.602