Year	Percent
1991	56.387
1992	56.044
1993	52.565
1994	52.013
1995	52.662
1996	51.403
1997	51.291
1998	51.353
1999	53.347
2000	53.77
2001	54.061
2002	53.983
2003	54.585
2004	54.401
2005	54.298
2006	54.736
2007	54.673
2008	53.877
2009	52.192
2010	51.405
2011	52.064
2012	52.551
2013	54.025
2014	57.287
2015	59.185
2016	61.266
2017	61.767
2018	61.74
2019	61.561
2020	61.294
2021	60.98
2022	60.705