Year	Percent
1991	48.298
1992	48.368
1993	48.391
1994	47.002
1995	47.128
1996	46.666
1997	45.823
1998	45.635
1999	44.622
2000	45.545
2001	46.745
2002	47.725
2003	49.011
2004	46.784
2005	46.181
2006	45.977
2007	45.49
2008	45.638
2009	44.349
2010	44.99
2011	46.671
2012	43.465
2013	43.557
2014	43.217
2015	42.267
2016	41.063
2017	40.564
2018	39.69
2019	38.759
2020	37.956
2021	37.229
2022	36.433