Year	Percent
1991	43.513
1992	43.667
1993	43.109
1994	41.582
1995	41.889
1996	41.176
1997	45.096
1998	44.521
1999	43.073
2000	42.336
2001	43.614
2002	44.542
2003	44.477
2004	44.24
2005	45.407
2006	48.511
2007	49.97
2008	50.949
2009	46.687
2010	45.084
2011	45.709
2012	46.662
2013	47.918
2014	48.191
2015	49.575
2016	50.64
2017	50.973
2018	50.877
2019	50.694
2020	50.505
2021	50.274
2022	49.993