Year	Percent
1991	53.659
1992	44.984
1993	36.887
1994	31.4
1995	23.766
1996	21.812
1997	34.125
1998	36.813
1999	40.604
2000	44.833
2001	44.26
2002	44.08
2003	38.757
2004	41.511
2005	40.619
2006	46.886
2007	44.213
2008	45.086
2009	43.085
2010	47.05
2011	49.077
2012	48.076
2013	49.825
2014	51.105
2015	51.163
2016	50.416
2017	51.661
2018	52.344
2019	53.113
2020	53.941
2021	54.863
2022	55.726