Year	Percent
1991	47.045
1992	47.488
1993	47.77
1994	47.599
1995	47.51
1996	49.682
1997	49.667
1998	50.194
1999	50.591
2000	50.34
2001	50.33
2002	50.152
2003	49.966
2004	49.465
2005	49.066
2006	48.79
2007	48.296
2008	47.965
2009	47.039
2010	45.849
2011	45.086
2012	43.168
2013	41.978
2014	42.472
2015	39.13
2016	38.759
2017	38.577
2018	38.516
2019	38.461
2020	38.407
2021	38.354
2022	38.303