Year	Percent
1991	59.774
1992	57.929
1993	54.87
1994	56.768
1995	54.029
1996	55.261
1997	54.672
1998	52.666
1999	52.144
2000	50.387
2001	47.359
2002	43.279
2003	40.673
2004	42.407
2005	43.415
2006	43.679
2007	43.436
2008	43.36
2009	40.79
2010	42.241
2011	44.882
2012	43.839
2013	44.491
2014	46.059
2015	46.088
2016	45.72
2017	45.517
2018	45.311
2019	45.179
2020	44.984
2021	44.852
2022	44.745