Year	Percent
1991	54.303
1992	52.982
1993	51.796
1994	49.938
1995	51.339
1996	50.409
1997	49.259
1998	47.81
1999	46.373
2000	45.613
2001	46.728
2002	47.286
2003	46.425
2004	45.7
2005	46.918
2006	45.393
2007	45.437
2008	45.639
2009	42.878
2010	42.733
2011	42.904
2012	41.675
2013	41.57
2014	41.856
2015	43.473
2016	45.234
2017	44.697
2018	43.943
2019	43.281
2020	42.839
2021	42.593
2022	42.35