Year	Percent
1991	54.158
1992	54.095
1993	54.477
1994	53.201
1995	53.779
1996	53.76
1997	53.422
1998	54.427
1999	54.088
2000	55.087
2001	54.641
2002	55.804
2003	54.482
2004	54.806
2005	54.916
2006	55.156
2007	55.264
2008	55.003
2009	54.253
2010	54.543
2011	53.686
2012	53.117
2013	53.131
2014	53.102
2015	52.934
2016	52.84
2017	52.753
2018	52.67
2019	52.547
2020	52.359
2021	52.178
2022	51.954