Year	Percent
1991	79.179
1992	79.106
1993	79.027
1994	78.842
1995	78.28
1996	77.959
1997	77.678
1998	77.031
1999	76.763
2000	75.874
2001	75.288
2002	74.211
2003	72.737
2004	71.202
2005	69.743
2006	68.061
2007	66.814
2008	64.834
2009	63.028
2010	61.398
2011	59.992
2012	58.308
2013	56.707
2014	55.041
2015	52.82
2016	52.353
2017	51.045
2018	49.507
2019	48.064
2020	46.684
2021	45.381
2022	44.401