Year	Percent
1991	43.01
1992	41.951
1993	41.948
1994	43.448
1995	44.606
1996	46.97
1997	47.271
1998	47.15
1999	47.732
2000	48.746
2001	48.626
2002	48.11
2003	49.395
2004	52.769
2005	54.24
2006	54.33
2007	56.428
2008	54.636
2009	54.006
2010	50.192
2011	50.793
2012	49.397
2013	49.982
2014	48.797
2015	49.628
2016	49.161
2017	47.684
2018	46.419
2019	45.383
2020	44.447
2021	43.707
2022	43.1