Year	Percent
1991	55.606
1992	57.019
1993	52.721
1994	48.928
1995	48.575
1996	45.616
1997	47.073
1998	49.521
1999	49.31
2000	52.305
2001	53.246
2002	52.881
2003	52.255
2004	51.526
2005	50.614
2006	52.606
2007	54.152
2008	53.109
2009	50.33
2010	49.407
2011	49.886
2012	49.883
2013	50.45
2014	51.18
2015	52.069
2016	51.881
2017	50.638
2018	50.497
2019	50.553
2020	51.08
2021	51.48
2022	52.058