Year	Percent
1991	71.044
1992	71.717
1993	69.619
1994	66.087
1995	64.425
1996	62.972
1997	59.806
1998	57.793
1999	60.298
2000	62.132
2001	61.838
2002	62.675
2003	61.817
2004	62.601
2005	63.307
2006	63.273
2007	65.009
2008	65.879
2009	64.116
2010	65.187
2011	66.182
2012	67.118
2013	67.328
2014	67.678
2015	67.748
2016	67.986
2017	67.966
2018	67.662
2019	67.348
2020	66.919
2021	66.393
2022	65.878