Year	Percent
1991	44.832
1992	43.876
1993	42.918
1994	42.956
1995	43.246
1996	43.276
1997	43.206
1998	43.468
1999	44.54
2000	45.005
2001	45.525
2002	45.557
2003	45.347
2004	44.787
2005	45.177
2006	46.251
2007	47.438
2008	48.146
2009	48.692
2010	49.358
2011	50.665
2012	50.922
2013	51.639
2014	51.991
2015	52.305
2016	52.905
2017	53.202
2018	53.25
2019	53.34
2020	53.392
2021	53.388
2022	53.367